Screwball Serum

A mysterious concoction, often made by a Lethal Chef, that probably should not be rated as fit for human consumption. Someone, intentionally or not, ingests some of it, and strange things happen to body and mind. Unfortunately, side effects may be permanent in some cases.

Somewhat similar in effect to Mushroom Samba, but the weird effects here tend to happen more literally than metaphorically. See also Intoxication Ensues and Gargle Blaster.

Not to be confused with Psycho Serum.

Anime and Manga

 * Anthy's curry in Revolutionary Girl Utena--not only explosive, but causes the people who eat it to swap bodies.
 * In one episode of Sgt Frog, Keroro attempts to make a traditional New Year's soup by combining a bunch of different recipes, but the resulting concoction turns Angol Mois into a smiling maniac who forces the soup down everyone else's throats, even when it proves nearly-lethal to Keronians.
 * Akiko's special jam in Kanon, so much so that it received a nod in Clannad After Story.

Comic Books

 * Formula Fourteen in Land of Black Gold is supposed to be an additive to petroleum that makes it incredibly explosive, but the Thompsons mistake it for aspirin. Their hair starts growing very rapidly and in bizarre colors, and their mouths emit bubbles. The many-hued side-effects even persist into Destination Moon.
 * Happens in Asterix and the Laurel Wreath, with the added subversion that Obelix, who is an incredibly overweight Big Eater complains that it was "somewhat insipid" while the rest of the house turns technicolour and incredibly lethargic. However, their owner's drunkard son, is cured of his massive hangover by this concoction, which eventually led to the decline and fall of the Roman Empire.
 * After being whacked over the head with a menhir, Getafix starts producing this instead of the Super Serum in Asterix and the Big Fight.

Film

 * The 1950's screwball comedy Monkey Business.
 * Murdock's "special sauce". Two of the key ingredients are Cordite and anti-freeze, and it has been known to cause temporary facial paralysis.

Literature

 * The chewing gum meal in Charlie and The Chocolate Factory, which works wonderfully until the blueberry dessert stage.
 * George's Marvelous Medicine, also by Roald Dahl.
 * There's an Australian poem about 'Feral Mixed Grill', made from virtually every creature in the Australian outback (and probably illegal, given many of them are endangered or protected). It tends to turn the consumer into an outback animal themselves, temporarily.
 * We can't forget Nanny Ogg's chocolate pudding in Maskerade. All you need to know about its effects is the phrase "My boots caught fire on the second lap."
 * Most of her cooking seems to have a somewhat...enhancing effect. It's never explicitly stated what the Surprise of her "Bananana Soup Surprise" is, but apparently glancing at a ruler will help you visualize it.
 * And the Carrot and Oyster Pie; carrots to let you see in the dark, and oysters to give you something to look at.
 * "Wellll, they starts out as Maids of Honor... but they ends up as Tarts."
 * Ms Mush's mushroom surprise in the Wayside School series.

Live-Action TV

 * Toddlers and Tiaras has a somewhat troubling example. Alana's mother routinely gives her "go-go juice" at the beginning of pageants, which is Pixy Stix dissolved in a mixture of Mountain Dew and Red Bull. As expected, the child goes a little bit nuts.

Newspaper Comics

 * In Bloom County Oliver's father mistakenly drinks the extract of dandelions that Oliver was about to experiment on. It causes him to hallucinate that Erik Estrada is coming out of his belly button and later, while chewing Oliver out, envisions Brook Shields' head on his son's body.

Video Games

 * Akiko's 'special' jam in Kanon. Its contents and recipe known only to her, side effects on non-Akiko eaters include a distorted sense of reality, a visible aura of discolouration, and the violent urge to run away screaming at the sight of more of the stuff. To be completely fair, though, she's otherwise a very good cook.
 * Akiko's jam even makes an appearance in Eternal Fighter Zero as Akiko's Final Memory attack. Characters from Kanon that already know how horrible her jam is have special reactions during the attack; other characters simply eat it unwittingly.
 * World of Warcraft gives us the Nogginfogger Elixir diet drink--as in, it shrinks the ingester, makes them lighter than air, or turns them into a skeleton.
 * Then you have Deviate Fish (no, not THAT deviant), which can heal or buff the ingester--or shrink him, make him sleepy, or make him feel like throwing a party. Savory Deviate Delights, which are cooked versions of this fish, turn one into a pirate or a ninja.
 * Making one of these to escape the Body Horror inflicted on you by the titular character is the entire point of The Secret Island of Dr. Quandary.

Western Animation

 * Dr. Zitbags Transylvania Pet Shop -- the doctor mixes up a potion with "enough E-numbers to drive anybody loopy" so that Zombunny will actually get up and go deliver Easter eggs,instead of just sitting there. It works a little too well, as it's transformed into an egg-throwing whirlwind that pelts everyone with chocolate.
 * To transform into cartoon hero Super Chicken, millionaire playboy Henry Cabot Henhouse ingests Super Sauce (served up by sidekick Fred from a martini glass) - he goes through wild contortions in the 'transformation', but doesn't make any notable change.
 * This is mistaken for a curse in the My Little Pony Friendship Is Magic episode "Bridle Gossip": Twilight Sparkle's horn becomes limp and covered in blue spots; Pinkie Pie's tongue swells until she becomes The Unintelligible; Rarity's pelt and mane become long and frizzy like a sheep dog's hair; Rainbow Dash's wings get flipped upside down, leaving her completely unable to fly straight; Applejack gets shrunk to a few inches in height; and Fluttershy gets stuck with a deep, masculine voice.