Malfunction Malady

Being sick is no fun for anyone. There's the fever, the aches and pains, the need to sleep, the runny nose, and a plethora of other unpleasant symptoms to contend with.

For magical or powered characters in fiction, particularly in animation, the above can come along with a Malfunction Malady. Regular symptoms of the common cold or other condition may be compounded by Power Incontinence, or a form of it. Powered characters who come down sick may find their powers firing off uncontrollably with every sneeze.

Worse, when they attempt to use their powers intentionally, the result is a Magic Misfire - the effect they wanted affects the wrong target, inflicts a bizarre effect on some innocent bystander, fizzles, doesn't happen at all, or comes out completely random. Naturally, Hilarity Ensues.

Worse yet, sometimes the effects are caused by something perfectly natural, like puberty or pregnancy.

If this wasn't all bad enough, there is almost never an easy cure. Usually the hapless victim of the malady wonking their powers has to wait it out, or their friends and teammates have to go on a Fetch Quest for some strange, arcane, rare or mysterious item (perhaps a Flower From the Mountaintop) to get them over this disease and its dangerous side effects.

Use of this trope also tends to generate an Annoying Patient for any friend or family member nearby who isn't also sick or compromised by the sickness.

Anime and Manga

 * Negi from Mahou Sensei Negima creates gusts of wind when he sneezes. Wind that seeks out and strikes girls' clothing like a heat-seeking missile.
 * Turning the trope on its head, a magical overdose from Konoka's Healing simulated the effects of a high fever.
 * Esper Mami had the eponymous teenager's telekinetic powers disassemble items when she sneezed—thankfully she was lifting a truck, not a person, when she discovered this. I'm not sure if her teleportation going wonky when she got drunk counts.
 * A variation found in The Slayers: female mages suffer a severe loss in power when it's "that time of the month".

Fan Works

 * The Homestuck fanfic "SWIMMING WITH SHARKS" points out the potential for such with Terezi's abilities. She normally perceives the world synaesthetically, via smell and taste... But in the fanfic, she gets a cold, effectively making her blind and entirely debilitated.
 * There are several Harry Potter fics wherein wizards undergo a process called "magical maturity" at some point in their puberty, during which the witch or wizard leaps from childhood magic to full adult power. It is usually quite a bit like an intense fever, usually including disorientation or even hallucinations.  And the more powerful the witch or wizard is going to be, the longer and more severe it is.  In these stories, Harry usually undergoes a maturity fever of hitherto-unseen duration and intensity, and often has to be brought out of it artificially lest his own cosmic power kill him before it finishes manifesting.

Literature

 * In The Last Continent, The Librarian at Unseen University catches a cold and turns into something new every time he sneezes, thanks to his "morphic field" being weakened by his original transformation from a human into an orangutan.
 * The entire plot of The Exploits of Ebenezum (and further sequels The Wanderings of Wuntvor) by Craig Shaw Gardner revolves around this. Ebenezum, a talented hedge wizard, accidentally summons a demon and is somehow cursed by the Netherhells while sending him back. This causes him to develop an "allergy" to magic, interrupting every one of his spells with a thunderous sneeze. At first this is thought to be the work of said demon, but later even he proves unable to reverse it. So his bumbling apprentice Wuntvor has to help him get from one place to another looking for a cure. In case it wasn't obvious, this is a quite funny modern fantasy parody.
 * In Animorphs, Rachel suffered this after scanning an animal she was apparently "allergic" to. This caused her to randomly assume her various animal forms and only ended with her expelling the new shape by vomiting up an entire alligator.
 * In So You Want To Be A Wizard?, Nita and Kit unintentionally transport Fred the sentient white hole to them. White holes emit stuff - usually energy. Most of his mass and energy is stored in a temporal-spatial pocket so that he can travel at all, and the act of traveling has made him a bit woozy - it gives him a bad case of the hiccups. When he hiccups, he emits stuff. And by stuff...good luck trying to explain the Learjet that just appeared in the middle of the field.
 * In The Wheel of Time Elayne Trakand becomes pregnant, and the Aiel Wise Ones inform her that she will occasionally be unable to channel.

Live Action TV

 * I Dream of Jeannie: Jeannie coming down with a cold would cause "blink" effects and random things showing up that Tony had to get rid of.
 * Bewitched: The same thing happened with the witches and warlocks in Samantha Stevens' family. I'm sure it happened to Samantha, Serena, and Aunt Clara on separate occasions.
 * The Secret World of Alex Mack: Alex got bubble hiccups, sneezed herself into a puddle, and lost control of her electricity. Exposure to several chemicals in other episodes reacted with the GC-161 and made her sick in ways like: parts of her body randomly morphing into water, out of control aggression, and static electricity. On the other hand, there was the chili that gave her Super Strength...
 * Star Trek, "Plato's Stepchildren": One of the Platonians (or whatever they were called) was sick, and since they had telekinetic powers, that made furniture fly around as if there was a hurricane. Dr. McCoy cured him, and they showed their gratitude by forcing the Starfleet officers to star in a sadistic puppet show.
 * Sabrina the Teenage Witch used it at least twice. One was when Sabrina caught spellfluenza, which is a 24-hour sickness that causes one's powers to be transferred to the nearest person when one sneezes. Assuming they are the nearest person again during the next sneeze, the powers come back. Wouldn't you know it, the person who got her powers was Libby. The other was when Hilda caught punitis, a disease in which everything she said resulted in a bad Visual Pun occurring (for example, when she asked for some ice cream, a screaming disembodied eye appeared in the freezer).
 * In Charmed, witch pregnancy seems to result in a lot of unusual and uncontrolled magic effects, though this is explained more as the magical fetus messing with things than the mom's magic going haywire as a result of pregnancy.
 * Another example occurs in "Centennial Charmed" when Paige gets a cold and accidently teleports whenever she sneezes.
 * Smallville: Clark Kent discovers his super breath when he catches a cold, sneezes, and blows the barn door off its hinges and across the entire county, almost decapitating Lois. Much of the episode is spent trying to come up with believable reasons why the Kent barn door appeared in the middle of nowhere.
 * That's So Raven: When Raven becomes ill with the flu, she reads people's minds.

Western Animation

 * American Dragon: Jake Long had an episode like this.
 * Yin in Yin Yang Yo! came down with the WooFoo Flu which caused inanimate objects to come to life. She was the Annoying Patient for her brother Yang. Until he came down with it, and put Yo in the position of caretaker to the sick sibs.
 * This happened in a first season episode of Ben 10. Wildmutt was effectively blind, Fourarms was more disgusting and clumsier, and Heatblast became An Ice Person.
 * When Beast Boy got a cold in Teen Titans, every sneeze caused involuntary morphing.
 * When Starfire went through Tamaranian puberty, she developed a number of strange and unattractive features before returning to normal and having the ability to fire starbolts out her eyes.
 * Similar to Beast Boy above, her allergy to metallic chromium also causes her to sneeze rather explosively.
 * It was used as a gag in X-Men: Evolution that when Kurt had a cold he would teleport everytime he sneezed.
 * In an episode of The Fairly Oddparents, Cosmo's Phygigly Gland (which controls a fairy's transforming powers) starts acting up, necessitating a transplant from Cosmo's Evil Twin Anti-Cosmo.
 * A much earlier episode had Cosmo catching the "Fairy Flu", which caused him to randomly lose control over his powers every time he sneezed (one sneeze summoned a merry go round, another transported the house to the moon, etc.). For some reason, feeding him lots of sauerkraut cured him.
 * Genie in Aladdin also caught a cold that causes random objects to appear every time he sneezed, with the objects becoming more dangerous as the disease progressed.
 * Katara the waterbender gets sick like any ordinary person, but airbender Aang's sneezes launch him ten feet into the air; though that may be Aang being playful.
 * In Transformers: Beast Wars, Tarantulas infects Rhinox with a virus that makes him hiccup destructive bolts of electricity in the first season episode, "The Low Road." The episode plays pretty straight to the trope, with the other Maximals alternately nursing their new Annoying Patient and running on a Fetch Quest for the antivirus.
 * The plan ultimately turns on the Predacons when Rhinox gets sick of being an Annoying Patient and decides to inflict himself on them.
 * It's either an inversion of this trope or Cursed with Awesome, but every time Glitter the sidekick fairy sneezed in Kidd Video, she temporarily gained super strength. This troper doesn't recall if there was any explanation why sneezing did this for her.
 * This is Kidd Video, a perfect example of What Do You Mean It Wasn't Made on Drugs?. If they explained anything I'd have been amazed.
 * In one episode of Adventures in Care-a-Lot, Funshine got a case of Bubbles, which made him cough up bubbles every time he hiccuped and start floating away.

Web Comics
"Wilhelmina: when succubi hit puberty, their pheromone glands kick into high gear, and if they aren't careful, hiccups can set them loose. Why, a good sneeze could let a few dozen out at a time!"
 * Superhero Girl has a Genre Savvy roommate who expects the Malfunction Malady in this comic.
 * Eerie Cuties in Chapter 5 had a succubus with no control over producing those... bat-winged heart things.

Web Original

 * Ultra Man of the Global Guardians caught the flu, and during a sneeze nearly burned down a building with his heat vision. He also lost track of how much of his Super Strength to use while sick, and was constantly crushing objects or shattering them in his hands.
 * Street Fighter: "Hello, Ryu!" "Heddo, Ken!"
 * In Monster High, Frankie is shown to inadvertantly release electricity when she sneezes. And Abbey releases a burst of frosty air that can freeze things with her sneezes. But topping them both is Operetta, who's voice can reach supersonic levels, meaning supersonic sneezes. One sneeze from her shatters several windows and sends a few unlucky students flying out the door.