Jellyfish are some of the most unique creatures on the planet. They’ve been around longer than the dinosaurs. They don’t have brains, bones or blood. And they’re not even fish! So what are they?

Float along with Molly and cohost Rosie as they learn about the different parts of a jellyfish, hear from a jellyfish superhero, and talk to scientist Dr. Rebecca Helm about how jellyfish have babies. Plus, a tantalizing new Mystery Sound!

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ROSIE: You're listening to Brains On, where we're serious about being curious.

ANNOUNCER: Brains On is supported in part by a grant from the National Science Foundation.


ROSIE: This pool is really nice. Coming here was a great idea, Molly. And I'm loving these rainbow floaties.

MOLLY BLOOM: Right? I figured since we're going to talk about jellyfish, we should act like jellyfish. And in the wise words of Janelle Monet, just float.

ROSIE: Yeah, jellyfish seem super chill.

MOLLY BLOOM: That's what jellies are best at, just hanging out. They seem so peaceful, you know? One with the water. And why just talk about jellies when you can be the jelly?

ROSIE: Be the jelly.

BOTH: Be the jelly. Be the jelly.

SANDEN TOTTEN: Did somebody say jelly?

MOLLY BLOOM: Yes, we said jelly.

SANDEN TOTTEN: Perfect, because I've got a peanut butter sandwich in desperate need of some jelly. Can't have a PBJ without some J. Got any grape?

ROSIE: Sanden, we're talking about jellyfish. We don't have any grape jelly.

SANDEN TOTTEN: OK. What about strawberry?

MOLLY BLOOM: Sanden, no, we have no condiments here. We're just trying to chill. Go check the fridge in the kitchen.

SANDEN TOTTEN: All right, all right, don't get your tentacles twisted. You can go back to being the not-grape-jelly jelly.


MOLLY BLOOM: OK, no more distractions. Jellyfish don't get distracted. They just mine their blobby business.

ROSIE: Jellyfish don't do much, right? We need to figure out how to do nothing.

SANDEN TOTTEN: But we're always doing something. [GULPS] I'm eating a PB and J, and you're floating in the water. That's not nothing.

MOLLY BLOOM: Sanden, relax, dude. Be the jelly.

SANDEN TOTTEN: Well, I'm eating jelly. And if you are what you eat, well, I guess, I'm jelly. Hey, one more question, do jellyfish do cannonballs? Because I can't resist.

MOLLY AND ROSIE: Sanden, no!



MOLLY BLOOM: You're listening to Brains On from APM Studios. I'm your host, Molly Bloom, and I'm here with Rosie from San Marcos, California.

ROSIE: Hi, Molly.

MOLLY BLOOM: Today's episode is about the squishiest, stingiest superstars of the sea--

ROSIE: Jellyfish!


MOLLY BLOOM: Rosie, what do you think of when you hear the word "jellyfish?"

ROSIE: I think about those big jellyfish in groups that are, like, purple.

MOLLY BLOOM: Hmm, very cool. Have you seen these in real life or any jellyfish in real life?

ROSIE: I have. We were on a boat, and there were like all these jellyfish surrounding the boat, so we got to see a lot.

MOLLY BLOOM: Wow, that sounds really cool. Were any of them the glowing jellyfish?

ROSIE: I don't think so. They were, like, sort of small circles that are blue.

MOLLY BLOOM: Cool. So what did it feel like to be in that boat with all the jellyfish around?

ROSIE: It felt really, like, cool. Like, I've never seen that many jellyfish before. I was really happy and, like, surprised. But then I was like, what if the boat crashed? We would fall into all those jellyfish.

MOLLY BLOOM: Yeah, probably not wanting to go swimming with them makes a lot of sense. But from a distance, they were cool?

ROSIE: Yeah.

MOLLY BLOOM: Nice. And when you were on the beach recently, you said you saw a jellyfish too, right?

ROSIE: Mm-hmm. We saw it from up top. But then I had to go down and look at it closer.

MOLLY BLOOM: What did it look like? How big was it?

ROSIE: It was, like, three sand dollars maybe. It had, like, little bits of purple, but it was really, like, baby blue and clear.

MOLLY BLOOM: Oh very, very cool. So have you ever eaten a jellyfish?


MOLLY BLOOM: Where did you eat it?

ROSIE: In Korea at this, like, buffet thing.

MOLLY BLOOM: How was it prepared?

ROSIE: It was, I think, stir fried or something. But when you put it in your mouth, it was really soft and jello-y. But when you bited it, it was, like, crunchy.

MOLLY BLOOM: Oh, interesting. Did it taste good?


MOLLY BLOOM: Not your favorite. It's not your favorite yet. Maybe someday, you'll be like, oh, it's my favorite food. That's awesome that you tried it though.

ROSIE: Yeah, it was really sour.

MOLLY BLOOM: Mm. I wonder if that was the jellyfish or the sauce. It's hard to know. You'll have to try it again one day and let me know if it was the jellyfish or the way it was cooked, OK?


MOLLY BLOOM: Well, jellyfish are amazing, unique creatures. They've been on the planet for millions of years.

ROSIE: Yeah, jellyfish are so old.

MOLLY BLOOM: How old are they?

ROSIE: Jellyfish are so old, they're even older than dinosaurs.

MOLLY BLOOM: Right. Jellyfish have been around for at least 500 million years. That's about 200 million years before dinosaurs showed up.

ROSIE: Oh, oh, I've got another one. Jellyfish are so old.

MOLLY BLOOM: How old are they?

ROSIE: They're so old, they're older than trees.

MOLLY BLOOM: What? Older than trees? My mind is turning to jelly just thinking about that.

ROSIE: Mine too!

MOLLY BLOOM: It's pretty mind blowing. And even after all of that time, all those millions and millions of years, jellyfish never evolved to have things like bones or blood.

ROSIE: Right. And they don't even have any organs either. So no hearts and no brains.

MOLLY BLOOM: And you might be thinking, how does a brainless, heartless, boneless blob do anything at all?

RUBY GUTHRIE: Hey, that's exactly what I was thinking.

ROSIE: Whoa, Brains On producer, Ruby Guthrie?

MOLLY BLOOM: You came out of nowhere.

RUBY GUTHRIE: Well, they don't call me Ruby Jumpscare Guthrie for nothing.

MOLLY BLOOM: Do people really call you that?

RUBY GUTHRIE: Uh, no, I just made that up. People call me Rubes, but that does absolutely nothing for my street cred. You know it does wonders for my street cred? Knowing about jellyfish.

MOLLY BLOOM: Seamless segue.

RUBY GUTHRIE: Oh, thank you. I mean, maybe they should call me Ruby Seamless Segue Guthrie instead. But anyway, what was I saying? Oh, yeah, jellyfish. I think jellyfish are some of the most bananas, bonkers beings on the planet. For starters, they're not even fish. They're actually most closely related to coral or sea anemones.

ROSIE: Sea anemones, you mean those floppy, flower-looking things that clownfish hide in?

RUBY GUTHRIE: Yeah, yeah, like in Finding Nemo. Sea anemones, corals, and jellyfish are all a part of this same group called cnidarians. And they're all grouped together because they all sting.


MOLLY BLOOM: Whoa, I did not know that coral can sting.

RUBY GUTHRIE: They can. But before we get into jellyfish stinger specifics, we have to understand what a jellyfish is made of in the first place.

MOLLY BLOOM: Oh, yeah, we actually got a question about this from one of our listeners.

SHERRY: My name is Sherry from Belmont, California. My question is, what is the anatomy of a jellyfish? I was at the aquarium and we were at the jellyfish exhibit, and it made me wonder.

RUBY GUTHRIE: Ooh, I love this question. Jellyfish, like us, come in lots of different shapes, sizes, and colors. But they always share some basic things in common. Most of them have that round body with tentacles hanging down. And that round body is called a bell, which makes sense because it totally looks like a bell, right?


ROSIE: Yeah, or like an umbrella.

MOLLY BLOOM: Or a mushroom cap.

RUBY GUTHRIE: Exactly. And in that mushroom cap, umbrella-like bell body, there's more than meets the eye. The edge of a jellyfish's bell is lined with a little structures called rhopalia. These make it possible for jellyfish to sense light, vibrations, and even gravity.

MOLLY BLOOM: What else is inside the bell?

RUBY GUTHRIE: Well, there are three layers to a jellyfish. There's the outside, which is their skin, that's the first layer, followed by a thick jelly-like layer, that's the second layer. And then there's the third layer, which is their digestive system. It's called a gastrodermis. It's kind of like a stomach or just a pouch where food can go. It's connected to their mouths, which are right at the bottom of the bell. And turns out, their mouths are also their butts.

MOLLY BLOOM: Wait, what? The butt?

RUBY GUTHRIE: I know, totally wild, right? But it's actually pretty simple. Everything that goes in also comes out of the same place.

ROSIE: I think I know where this is going.

RUBY GUTHRIE: So jellyfish put stuff in their mouths like maybe some plankton or fish or even a crab--


--then they digest it.


And the stuff that they don't digest, all that leftover poop, well, it goes right out the same hole they were shoveling food into earlier.



ROSIE: Whoa, that's totally awesome and gross.

RUBY GUTHRIE: Yeah, to us, humans. It leaves a funny taste in the mouth, I mean, figuratively speaking, of course.


RUBY GUTHRIE: But for jellies, a mouth that is also your butt is the only way of life that they know.

MOLLY BLOOM: OK, so we've got the bell body covered.

ROSIE: Complete with their mouth butts.

MOLLY BLOOM: Of course, can't forget the mouth butts. But what about the tentacles?

RUBY GUTHRIE: The tentacles are super important tools for jellyfish. It's how they catch their next meal, using their stingers. Each tentacle is covered with thousands of teeny tiny microscopic stinging cells.

MOLLY BLOOM: Cells are the building blocks of all living things.

RUBY GUTHRIE: Right, but these are special cells called cnidocytes. You can picture them like itty bitty tubes with tiny little arrows coiled inside. And when the cnidocyte cells are triggered, like a jellyfish brushes its tentacle against something, the teeny tubes open up and let in water, which launches the arrow-like stingers to inject venom.


The venom stuns the prey so the jellies can gobble them up for lunch.

ROSIE: Pretty hardcore for something with no backbone.

RUBY GUTHRIE: It's true. There's nothing more hardcore than having stinging tentacles and a mouth for a butt. I mean, not even the nickname Ruby Jumpscare Guthrie can beat that.

MOLLY BLOOM: Do you think that name will really catch on?

RUBY GUTHRIE: Maybe if I-- sneak over here. Boo! Did I scare you?

MOLLY BLOOM: Afraid not.

ROSIE: Uh, no. Maybe stick to segues and jelly facts.



MOLLY BLOOM: OK, so we've learned all about what makes up a jellyfish.

ROSIE: They're boneless, brainless blobs, and have survived for millions and millions of years.

MOLLY BLOOM: They have round bodies called bells and use their tentacles to catch and eat their food and also sense the world around them.

ROSIE: And you can't forget that their mouths are also their butts.

MOLLY BLOOM: Very unforgettable. And you know what else is unforgettable? The way jellyfish have babies. To learn more, we called Rebecca Helm. She's a biologist at Georgetown University who studies jellyfish.

ROSIE: And she's on the phone right now. Hi, Rebecca.


ROSIE: How do jellyfish make for jellyfish?

REBECCA HELM: Jellyfish have a couple different ways to make more jellyfish. One of my favorite ways is a process where the jellyfish will go through a kind of transformation. So jellyfish start life looking nothing like jellyfish. They look like little, tiny sea anemones. They have this body about the size of a breadcrumb and a whorl of tentacles around the top and a mouth in the middle.

And they catch food and they eat and they grow, and that's their job. But when they go through this transformation, the body looks less like a little sea anemone and more like a tiny stack of pancakes. Each little pancake will pop off and become a tiny jellyfish.

ROSIE: So sort of like a frog?

REBECCA HELM: Kind of. It would be like a tadpole could turn into, like, 20 frogs.


REBECCA HELM: Weird, right?

ROSIE: Yeah.

REBECCA HELM: They kind of look like snowflakes. And all the little snowflake jellyfish stacked together look like a pinecone. And so the first person to discover it named it pinecone. But he named it in another language, so we call it a strobila, which means pinecone.

ROSIE: Oh, that's cool.

REBECCA HELM: It's really cool, and they do it at least once a year over and over and over again. So you can have a polyp that's like 100 years old, and every year, it'll produce 10, 20, 30 jellyfish in a little stack.

ROSIE: Oh, that's really cool.

REBECCA HELM: It's really fun to watch.

ROSIE: I read there's one kind of jellyfish that can live forever. How does that work?

REBECCA HELM: We don't really know exactly how it works, but it's a really neat story. The jellyfish grows up from a polyp to a jellyfish. But then if the jellyfish gets hurt or injured in some way, it'll shrivel into this little ball. It looks like a wadded up piece of paper just kind of crumpled up on the sea floor. And out of that little ball, a new tiny polyp will grow.

So it sort of gets to start its life cycle all over again. It's like if you had a favorite frog friend and your frog was hurt in some way, your frog, instead of dying, would just turn back into a tadpole, eat a bunch more, and then metamorphose back into a frog again.

ROSIE: Oh, that's really cool.

REBECCA HELM: It is, I mean, so confusing and cool to think about. What we don't know is if it can do this, like, rebirth as many times as it wants or if, after a while, it starts to get, like, kind of tired. So in order to really know if something can go on forever, you kind of have to watch it forever. And no one's been watching them that long, so we've got a little ways to go before we know if it's really immortal. But we definitely know it can start its life over again from the beginning if it wants to.

ROSIE: I'll commit my life to watch it forever.


MOLLY BLOOM: Thank you, Rosie.

REBECCA HELM: That's very appreciated.

ROSIE: What's your favorite jellyfish fact?

REBECCA HELM: I have so many, but I think one thing I really like about jellyfish is that a lot of people say they don't have brains, and that's mostly true but it's not the whole truth because they actually have these little tiny, itty bitty sort of baby brains all around the edge of their body. Yeah, so all along the edge of that bell shape, they have these little dots.

And each dot has, like, a tiny eye and a tiny ear and a tiny nose and a tiny brain. And they have, like, eight of them, and they all talk to each other. So yeah, it's weird.

ROSIE: It's sort of like a house, like eight people living in one, like, jellyfish house.

REBECCA HELM: That's such a good way to put it. And if you want to decide what to do with your big moving house, you have to talk to all your other people. And in the case of jellyfish, at least three have to decide they want to go somewhere, and then the house will turn.

ROSIE: One question that I was really curious about was whether jellyfish can sting each other.

REBECCA HELM: Yeah, they can. Some jellyfish eat other jellyfish, so--


REBECCA HELM: --they can absolutely sting one another. But in the same species, no, they can't sting each other.

ROSIE: We also heard that jellyfish are getting more common in the oceans. What's going on there?

REBECCA HELM: Yeah, there have been some studies, some scientists that have found evidence that some jellyfish are getting more common. But there are a couple things going on here. The first thing is, if you go to the ocean and there are tons of jellyfish, everyone will tell you because everyone gets stung. But not a lot of people report when there aren't any jellyfish. So we sort of are used to hearing when jellyfish are around but not when they're missing.

And that means that sometimes we don't notice when a species of jellyfish is actually on the decline or not doing very well. We just don't notice that it's gone.

ROSIE: That's sad.

REBECCA HELM: It is kind of sad. But there are some jellyfish that are also increasing. Certain jellyfish like the moon jellyfish from Japan is now in San Francisco and Florida. It's all over the world. It's traveled with people on the bottoms of ships as polyps. And then it will go through that pinecone phase and bud off all those snowflake jellyfish babies and start a new life in a new city and a new bay.

MOLLY BLOOM: Rebecca, I'm wondering, when you were Rosie's age-- Rosie is nine-- were you interested in jellyfish?

REBECCA HELM: I was, I was actually really interested in jellyfish. I thought they were so interesting and weird. And one of the things I wanted to be when I grew up was a jellyfish biologist, but I also wanted to be a cowgirl for a while. But yeah, I really liked jellyfish from a very young age and wanted to just study them. And I'm really happy that I get to do it now as an adult.

ROSIE: Thanks for answering our questions, Rebecca.

REBECCA HELM: Thank you for having me.

ROBOTIC VOICE: Buh, buh, buh, buh, buh, buh, buh, buh, Brains On.

MOLLY BLOOM: OK, Rosie, it's time for the--


CHILD 1: (WHISPERING) Mystery sound.

MOLLY BLOOM: Are you ready to hear it?


MOLLY BLOOM: All right, let's hear it.


OK. What in the what? What do you think?

ROSIE: I think it's maybe like someone, like, crushing something or walking on something like maybe rocks or gravel.

MOLLY BLOOM: Totally, that's a really good guess. Do you want to hear it again?

ROSIE: Yeah.





Oh, man, I do not know what this is either. To me, it sounds like some kind of monster eating a snack.

ROSIE: Yeah.

MOLLY BLOOM: I don't think that's it. What else do you hear?

ROSIE: When I heard it the second time, it sort of sounded like a dog eating something.

MOLLY BLOOM: Hmm, mm-hmm. So we both heard eating that time?

ROSIE: Yeah, or like maybe-- OK, this is really out there, but maybe like a dog squishing a, like, plastic water bottle in their mouth.

MOLLY BLOOM: I love that. That is not that out there. I'm into it. You know, we've had people hitting two frozen hot dogs together as a mystery sound, so it could be literally anything. Well, we're going to hear it again, get another chance to guess and hear the answer at the end of the show.


Hey, friends, we're working on an episode about memory, and we want to hear from you. Do you ever use a song or a rhyme to help you remember something like A, B, C, D? That helps me remember the order of the alphabet. Rosie, do you have a rhyme or a song that helps you remember something?

ROSIE: Yeah, like how to spell the word friend.

MOLLY BLOOM: Oh. Can I hear it?

ROSIE: (SINGING) F-R-I-E-N-D, you're a good friend to me.

MOLLY BLOOM: Oh, we love that. That Is very handy. Yeah, it's kind of a tricky word to spell. I'm going to sing that next time I have to write it. Very nice. Well, listeners, we want to hear from you. Record yourself singing or reciting, and send it to us at It can be something you learned in school or you can make up something totally random that helps you remember something very silly. And while you're there, you can send us mystery sounds, drawings, and questions.

ROSIE: Like this one.

CHILD 2: My question is, why does food expire?

MOLLY BLOOM: Again, that's

ROSIE: And keep listening. You're listening to Brains On. I'm Rosie.

MOLLY BLOOM: And I'm Molly. And today, my jam is jelly.

ROSIE: Jelly fish that is.

MOLLY BLOOM: Right. We're learning all about those brainless, boneless wonders with stinging tentacles and multi-purpose mouth butts.

ROSIE: And while jelly fish may seem pretty simple on the surface, they've actually got a lot of cool superpowers.

MOLLY BLOOM: Yeah, jellyfish can do some amazing things, the sort of stuff that would make any superhero totally jealous.

ROSIE: You mean totally jelly.

MOLLY BLOOM: Right. Here, let's learn more about the super side of these sea squishies.


MAN: Coming soon to the MCU-- that's the Marine Cinematic Universe-- it's a brand new superhero unlike any you've seen before. She doesn't fly. She doesn't jump. She just floats. Wait, is that right? It is? OK. Crime isn't ready for this hero. It's Super Jelly.

SUPER JELLY: That's right. I have all the powers of a jellyfish because I am one.

MAN: Wait, seriously? You're just a jellyfish?


MAN: Ugh, I thought I was narrating a movie for someone cool like Shark Dude or the Aquamarine, you know, hail, denizens of the deep. Pow, pow, pew! They have really cool powers.

SUPER JELLY: Oh, I have cool powers too. Like, did you know I'm loaded with venom?

MAN: Pshh, yeah, right. You don't look very venomous, more squishy.

SUPER JELLY: That's because my stingers are very, very tiny and hidden in my tentacles. They're smart too. My cells know not to sting myself because that would be Ouch City. Pretty tough, huh?

MAN: How painful could it be?

SUPER JELLY: Well, it depends. Some can be pretty painful. The box jellyfish is considered the most venomous creature in the ocean. It's super painful and even sometimes deadly. Want to feel?

MAN: Um, nope, I'm good.

SUPER JELLY: We can create our own light so that even deep in the ocean, we're shining bright like stars.

MAN: OK, that's actually pretty cool.

SUPER JELLY: But that's not all I can do. Some jellyfish can regrow body parts. Comes in handy if something chomps you. We can be super small like the size of a golf ball or super big. The lion's mane jellyfish can have tentacles that make it longer than a blue whale. Plus we're natural survivors.

MAN: You mean you can survive an epic super-powered battle?

SUPER JELLY: Those are nothing. Jellyfish have survived multiple mass extinctions, that's when a huge number of living things bite the dust in a short amount of time.

MAN: Oh, like when all the dinosaurs died?

SUPER JELLY: Yep, we survived that and plenty of other catastrophic events because we're built to last. We've been around for 500 million years and will probably be around for millions more. That's what makes us so super.


MAN: But I think I know your weakness, your kryptonite, if you will.

SUPER JELLY: Um, hungry sea turtles?

MAN: No. I heard there's a magic cure for your stings.

SUPER JELLY: Oh, I-- I don't think there's any--

MAN: I've heard I can just stop the sting with some number one.


MAN: You know, little tinkle juice.

SUPER JELLY: Excuse me.

MAN: Wash it with wee wee?

SUPER JELLY: Beg your pardon.

MAN: Pee on it. I heard pee pee makes the jelly ouchie go bye bye.

SUPER JELLY: Oh, that myth? Yeah, don't do that.

MAN: Why not?

SUPER JELLY: Well, urine or pee pee, as you called it, actually can cause any unreleased stinger cells to release, which makes the sting worse. Fresh water does this too. Your best bet actually is to rinse the jellyfish out with salt water.

MAN: Good to know, don't put pee pee on a jellyfish sting. All right, I admit it, you've got some cool powers. But, like, you just float. Don't you need to stop crying or something to be a superhero?

SUPER JELLY: You ever seen a bank robbery in the ocean? I didn't think so. You're welcome.

MAN: OK, then, thanks for all the neat info. I guess I should wrap up then, right? So if you'll excuse me-- [CLEARS THROAT] she floats. She stings. She regrows body parts. And pee pee can't stop her. Coming this summer to a beach near you, it's the latest hero to rock your world. Get ready for Super Jelly!

SUPER JELLY: It's me. So tough.

ROBOTIC VOICE: Brains, brains, brains on.

MOLLY BLOOM: Well, Rosie, given how mighty the jellyfish is, it would make sense if you confused them for world class fighters. That reminds me, you want to play a little game?

ROSIE: Sure.

MOLLY BLOOM: OK, we're going to play jellyfish or wrestler. [BELL CHIMES]

It's pretty simple. I'm going to give you a name, and you tell me if it's a type of jellyfish or a professional wrestler. Are you ready?

ROSIE: Mm-hmm.

MOLLY BLOOM: OK, first up, cannonball. Jellyfish or wrestler?

ROSIE: Ooh, I'm sort of on the fence about this one.

MOLLY BLOOM: It's a tough one.

ROSIE: OK, I'm going to go with wrestler.

MOLLY BLOOM: I'm sorry to say that it's actually a jellyfish.


Although, there should be a wrestler name that. So wrestlers, the name is available if you need it. So if you live on the South Eastern coast of the US, you're probably pretty familiar with cannonball jellies. They're also known as cabbage-headed jellies or jelly balls, and they're a popular jellyfish for humans to eat actually. They're often dried out, and then you can eat them in their dried up form. Yum. OK, here's the next one, gold dust. Jellyfish or wrestler?

ROSIE: I feel like if I kind of say jellyfish, it's going to be a wrestler. And if I say wrestler, it's going to be a jellyfish.

MOLLY BLOOM: So you've got to say one. What are you going to do? What are you going to say?

ROSIE: I think I'm going to say wrestler.

MOLLY BLOOM: You are correct.


Nice work. Gold dust is a wrestler. There is not a gold dust jellyfish. However, there are golden jellyfish which have a warm yellow color. And get this, they're only found in Jellyfish Lake. That's a real lake on the island of Palau in the Western Pacific. Some jellyfish can live in fresh water. Pretty cool. All right, are you ready for another one?

ROSIE: Mm-hmm.

MOLLY BLOOM: The next one is sting. Is that a type of jellyfish or the name of a wrestler?

ROSIE: Oh, I really want to say jellyfish, but I have feelings to a wrestler.

MOLLY BLOOM: So what's your answer?

ROSIE: Cannonball was an extreme name for a jellyfish, so I'm going to say it is jellyfish.

MOLLY BLOOM: I'm sorry, but it's actually a wrestler.


ROSIE: I knew it.

MOLLY BLOOM: [CHUCKLES] You know, maybe sting was inspired by jellyfish because they sting, you know?


MOLLY BLOOM: So not too far off. All right, last but not least, the pink meanie. Jellyfish or wrestler?

ROSIE: It sounds really familiar.

MOLLY BLOOM: What do you think?

ROSIE: You know, two of them have been wrestlers and only one has been a jellyfish, so I think it's going to be a jellyfish.

MOLLY BLOOM: And you are correct.


Excellent use of logic. We love it. So yes, pink meanie is a jellyfish. It has a bunch of fluffy pink tentacles, and it kind of makes it look like it's wearing a tutu. They're big and they love to eat other jellyfish, particularly moon jellies. Rosie, excellent work. Who knew jellyfish and wrestlers both had such awesome names?

ROSIE: Yeah.


Jellyfish have been around for hundreds of millions of years. They have round bell bodies and long tentacles.

MOLLY BLOOM: They don't have brains, bones, or blood.

ROSIE: But they do have mouths that are also their butts.

MOLLY BLOOM: And they make new jellyfish through a process called strobilation.

ROSIE: Jellyfish are like superheroes. Some can glow in the dark. Others can regrow body parts. And some even have super powerful stingers.

MOLLY BLOOM: And if you do get stung, don't pee on it.

ROSIE: Trust us.

MOLLY BLOOM: That's it for this episode of Brains On.

ROSIE: This episode was written by Ruby Guthrie and Sanden Totten with production help from Molly Bloom, Marc Sanchez, Anna Weggel, Rosie DuPont, Aron Woldeslassie, Molly Quinlan, Nico Gonzalez Wisler, and Anna Goldfield.

MOLLY BLOOM: It was edited by Shahla Farzan and sound design by Rachel Brees. We had engineering help from Nick Ritchie. Many thanks to Faye Kelling and Serena Kelling. Beth Perlman is our executive producer. The executives in charge of APM Studios are Chandra Kavati, Alex Schaffert, and Joanne Griffith.

ROSIE: Brains On is a non-profit Public Radio program.

MOLLY BLOOM: There are lots of ways to support the show. Head to

ROSIE: While you're there, you can subscribe to our Smarty Pass. It lets you listen to ad-free episodes and other fun bonus stuff.

MOLLY BLOOM: And you can submit your questions and mystery sounds. Speaking of, Rosie, you ready for that mystery sound again?

ROSIE: Let's do it.


MOLLY BLOOM: Oh, man, it sounded real squishy that time. I don't know. What do you think?

ROSIE: It was sort of disturbing that time.

MOLLY BLOOM: [CHUCKLES] The more we hear it, the more we're disturbed by it. Yeah, what do you think? Any other guesses?

ROSIE: I think it's either, like, someone doing that ASMR thing with their mouth, like, chewing something like [CHEWING]

Or, like, someone squishing or crushing a rock.

MOLLY BLOOM: Great guesses. You ready for the answer?

ROSIE: Mm-hmm.

MOLLY BLOOM: Me too. Here is the answer.

AUSTIN: Hi, my name is Austin. I live in Exton, Pennsylvania. That mystery sound was me pulling my wet rashguard away from my stomach. I wear a rashguard to protect my arms from the sun.


ROSIE: That was really far away from my answer.

MOLLY BLOOM: Yes, neither of us got so close. So yeah, the rashguard, that's like those long sleeve swim tops. And I guess Austin had gone in the water and gotten wet, and there was kind of like a suction thing happening between the swim top and the belly. I guess I'm going to have to try that next time I go swimming because that sound was very interesting.

ROSIE: Very interesting.



Now it's time for the Brains Honor Roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives.



COMPUTER: Brains On.

We'll be back next week with more answers to your questions.

ROSIE: Thanks for listening.

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