A waterbed is a mattress that replaces the internal foam and springs with, you guessed it, water. In fiction, the water is often used to create absurd situations that would be unlikely — if not outright impossible — on a spring or foam mattress. The flowing nature of the fluid is often exaggerated, and water-related jokes are made at the expense of realism.
Real Life waterbeds were designed in the 19th century for hospital purposes, as spring-based mattresses often caused bedsores. Popular Science Fiction author Robert A. Heinlein is often credited for their quick rise to popularity in America during The '70s and The '80s, due to including a high level of speculative detail in some of his fictional works. As the new waterbed design swept the nation, many creators responded with a wave of jokes based on their (mis)use. However, the production of waterbeds has greatly decreased since their peak in the 80's, and tends to be a Forgotten Trope, more common in older media than in current fiction. Their relative obscurity in the modern day can cause an Aluminum Christmas Trees effect to those who have never encountered them in real life. Works featuring waterbeds are thus generally dated to the 1970's or 1980's.
Waterbeds encourage the absurd; they were celebrated for their novelty, but their squishy and bouncy nature, as well as the inconvenient way they can rupture and spray water everywhere, have tied them to comedy. You might find fish living in the bed, perhaps intentionally or maybe they swam upstream. If characters try standing on the bed, they'll quickly lose their balance and end up bouncing around as if they were on a trampoline. Such absurdisms are based on Rule of Funny, given the furniture's Awesome, yet Impractical status.
Compare Gelatinous Trampoline, Solid Clouds, Springs, Springs Everywhere, and Trampoline Tummy, which have similar jiggly and/or bouncy properties. If everything seems to be made like a waterbed, that may be Rubbery World instead. Waterbed mishaps (causing varying degrees of flooding) overlap with Murphy's Bed. Does not usually overlap with Soft Water, unless one were to use it as a landing zone without it rupturing or the person being injured.
- One Josie and the Pussycats story has the trio visit a shopping mall. There, they are invited to test out a waterbed. After Josie and Valerie try it and like it, Melody gets cajoled into a try. She's reluctant at first, but soon warms to the undulations and gets quite bouncy with it. She attracts such a group of gawkers that the store manager hires Melody as a demonstration model.
- Garfield: In the December 1, 1979 strip, Jon takes Garfield to their neighbors, but unfortunately, Garfield tries to sharpen his claws on their waterbed. Jon groans that their neighbors will never invite them over again.
- Peanuts: A 1975 arc has Peppermint Patty inviting Snoopy over to keep her company while her parents have night shifts. When burglars rob the house in the middle of the night, Snoopy can't scare them off since he's bouncing on his waterbed and can't get off. Peppermint Patty and even Marcie come over to save him, but they get stuck bouncing on the bed too.
- A Goofy Movie: The Goofs' room at the Neptune Inn in has large clear waterbeds with live fish in them.
- Race for Your Life, Charlie Brown: Two years after the aforementioned Peanuts comic strip sequence, there is a similar incident in which Peppermint Patty gets to sleep on a waterbed as leader of the girls' group in a camp. Once she falls asleep, Snoopy enters the girls' tent to kiss the girls goodnight. When he jumps on Peppermint Patty's waterbed, the resulting waves send both Patty and Snoopy bouncing uncontrollably, making a great deal of noise. Marcie then grabs Peppermint Patty, only for Marcie to bounce uncontrollably on the waterbed with Peppermint Patty. Snoopy then bounces out of the waterbed and returns to his tent.
- The titular character of Edward Scissorhands has quite a bit of difficulty with his new waterbed after moving to the suburbs. He jiggles around on it hopelessly for a while, and then, to make matters worse, his sharp hand-blades actually puncture the bed, sending streams of water everywhere.
- Planet Terror: Roughneck barbecue chef JT surprisingly has a swank bachelor pad in the back of his restaurant, the Bone Shack, complete with a waterbed. El Wray bounces on it and quips, "This must be the real Bone Shack."
- X-Men: Days of Future Past: When Wolverine first time-travels to the past, the fact he wakes up in a waterbed serves as one of the many details to make it clear that he's back in the 1970s. Later in the same scene, he accidentally stabs the bed with his claws, causing water to spray out.
- A Nightmare on Elm Street 4: The Dream Master: Joey dreams of seeing a nude model swimming inside his waterbed. Then Freddy appears, slashes through the bed, stabs Joey and drowns him. In the real world, Joey's corpse is found floating inside the bed, despite the mattress being intact.
Freddy: How's this for a wet dream?
- A Saget-era clip on America's Funniest Home Videos depicted a couple having trouble getting out of a waterbed.
- Growing Pains: When Mike moves out of his parents' house to an apartment over their garage, one of the first purchases that demonstrates his "independence" is a waterbed, which is used in assorted comedic ways for the remainder of the series.
- Last of the Summer Wine: The plot of one episode has the trio trying to deliver a waterbed to Barry, as a surprise for his wife. At the very end of the episode, as he's about to take her upstairs and show it to her, he feels water dripping on his head...
- On My Name Is Earl, Joy and Darnell have a waterbed. Darnell is shown filling it up not long before their wedding. (Curiously, Joy's parents own a waterbed store, but the waterbed is explicitly stated to have come from a nearby flea market.) When Joy pretends she's still married to Earl, she's hopping around on the waterbed pretending she's having sex with her "husband" who's newly "back from the war." Also, when Joy is acting as a surrogate for her half-sister, she falls into the crevice between the mattress and the bedframe, and Darnell has to help her out.
- Roseanne: While shopping for a new mattress, Dan and Roseanne have fun belly-flopping onto a waterbed. When a salesman asks if he can help them, Dan jokingly orders piña coladas.
- The X-Files: Mulder's waterbed is a central motif in the "Groundhog Day" Loop episode "Monday" — specifically, Mulder waking up on it and discovering that it sprung a leak marks the start of every new time loop. It also plays on his character a little, given how he is incapable of sleeping in regular beds (instead, he sleeps on his sofa in most episodes).
- The Legend of Zelda: Breath of the Wild: Link can go to the inn in Zora's Domain and sleep on a Blissful Waterbed for a feenote . Once he pays the fee, there's a sound effect of Link bouncing and giggling on the waterbed, which the player does not see, though it is implied that the innkeeper, being across from the beds, sees Link bouncing. Given the equipment Link uses in his adventure, the Blissful Waterbeds are apparently indestructible, which is why the innkeeper says nothing about Link's behavior on the Blissful Waterbed.
- Cream Heroes: Claire buys a couple of small, rubber waterbeds for her cats to play on. Most of the cats aren't too keen on the way they feel and run off them as soon as she puts them on. The exceptions are Chuchu and Lala. Unfortunately the latter has her claws out and causes the inevitable leak.
- Adventure Time: In "Belly of the Beast", when Finn and Jake find a flock of bears partying inside a monster's belly, they try to convince them to leave, and are directed to the Chief, Party Pat, by a young bear named Cubby. Party Pat sleeps on the monster's heart, which Cubby describes as, "it's like a blood waterbed."
- Arthur: In the episode "Jenna's Bedtime Blues", Jenna attends a sleepover despite suffering from a secret bed-wetting problem, and wins a game that lets her sleep on Muffy's waterbed. This prize gets her very concerned that she's going to embarrass herself in front of her friends by having to feel water beneath her as she sleeps. Sure enough, she does have water-themed dreams, but they turn out to be just dreams (and Muffy's brooch accidentally causing a leak), letting Jenna make it to morning.
- Beetlejuice: In one episode, a vampire targets Lydia's mother and misses her, leaving a pair of holes in the waterbed.
- In one episode of Ed, Edd n Eddy, the boys are playing in the junk yard and come across an old van that clearly used to be a shaggin' wagon, complete with a waterbed in it. Naturally, they're soon bouncing on it.
- Garfield and Friends: In the episode "Beddy Buy", after Garfield broke his old pet bed, Jon and Garfield go to a shopping mall to look for a new bed for Garfield. Garfield tries out various beds, most of which he finds uncomfortable. He warms up to a waterbed up until he claws it, causing the waterbed to leak.
- Mission Hill: Andy works at a waterbed store, Ron's Waterbed World, and one episode begins with a married couple coming in to complain that their bed broke and get a refund. Andy denies the possibility of the bed just breaking for no reason, but the husband brought proof; a Home Porn Movie that he and his wife were filming at the time. The wife is mortified as her husband shows Andy the tape, out in the open and in full view of the other customers and employees, who all cheer as the bed breaks as they both climax.
Andy: Okay, the bed broke. But you gotta admit, the timing was pretty good!
- Wander over Yonder: In the episode "The Prisoner", Wander is jumping on a waterbed, with it bursting afterwards.
- There's a similar phenomenon called the lawn bubble in which after a rainstorm or a water main rupture, water is collected under the sod, creating the effect of a waterbed that doubles as a small-scale Rubbery World. Watch this video and see for yourself.
- The Monterey Bay Aquarium in Monterey, CA has the Coral Reef Kingdom in the Splash Zone & Penguins area. Within the soft safe zone with padded flooring, children under 34" tall can bounce on the waterbed.