Sleepwalking

Somnambulism, commonly known as sleepwalking, is the phenomenon where a person, while sleeping, performs physical activities, often with their eyes open but unresponsive to the world. Within the real world, the sleepwalker will typically have their eyes open and will move as normal, if sometimes a bit slower as if tired. Any complex action that is performed while awake may be replicated while sleepwalking, including unlocking of doors, catching trains, driving cars, even sex and murder. The sleepwalker typically avoids obstacles, but still may be injured by non-routine events such as tripping hazards or closed doors. The disorder is common in children, but is typically grown out of. It is rarer in adults and consistent bouts of sleepwalking may indicate various psychological or brain disorders. Because sleepwalking typically occurs outside of REM sleep, dreams very seldom correlate with the actions while sleepwalking --contrast Dream Action Leak.

Likely symptoms include:
 * Eyes open during sleep
 * May have blank look on face
 * May sit up and appear awake during sleep
 * Walking during sleep
 * Performing other detailed activity of any type during sleep
 * Not remembering the sleepwalking episode when they wake up
 * Acting confused or disoriented when they wake up
 * Rarely, aggressive behavior when they are awakened by someone else
 * Sleep talking that does not make sense

In fiction, sleepwalking is generally portrayed with the sleepwalker having both arms extended in front of them and eyes closed (and in some extreme cases, blindfolded). The sleepwalker will again perform complex actions, but will almost always have an uncanny ability to avoid dangers in their world that they really shouldn't be aware of.

Folklore regarding sleepwalking states that waking a sleepwalker is dangerous, but in reality, the worst that may happen is confusion as they awake in a strange place.

See also Talking in Your Sleep, a related phenomenon, and Escort Mission or Badly Battered Babysitter for the frequent trope involving other characters trying to shepherd the sleepwalking character past danger without waking them due to the old wives' tale.

Anime and Manga

 * Asuka attempting to kiss Shinji in his sleep in Neon Genesis Evangelion
 * Fam from Last Exile Fam the Silver Wing has a pretty bad case, especially since she's a Sky Pirate. The first scene of the entire show is her stripping off, opening the hanger door of their airship and walking out, saved only by a rope with a bell on it tied to her leg. Episode 4 also shows that there's a mat placed below the entrance to her loft bedroom to cushion her inevitable falls.
 * Ranma One Half: Akane takes this a step further. She fights in her sleep.

Comedy

 * Comedian Mike Birbiglia has this problem, which he details in his book Sleepwalk With Me.

Comic Books

 * The Marvel Comics character Sleepwalker, whose body is taken over by an alien being at night when he's asleep.
 * One of Venom's early appearances -- as the symbiote rather than as just clothes, and before he was separated from Spider-Man -- had him take Peter Parker out for a swing while Parker was completely asleep. Parker later wonders why he's so tired.
 * In Marvel Star Wars, Luke once goes into a Force-induced coma where he has to fight a Vader-shaped manifestation of his own fear. Meanwhile, he gets captured, stripped, and Strapped to An Operating Table. As he starts to win, his eyes open, he breaks free of the table, and he fights off a horde of guards while still fighting in the dream. He's rather surprised when he wakes up.

Film

 * Trope Maker for the "arms extended in front" pose is The Cabinet of Dr. Caligari.
 * Frankenstein's Monster and zombies are usually portrayed as walking like this, with hands outstretched. While they're not technically asleep, they are resurrected dead -- death often being compared metaphorically to a permanent sleep. In the original Universal film series Frankenstein's Monster only did this after an incompatible brain transplant, making him blind. And arguably, making him no longer the same character. It was then Ygor's brain in the monster's body. Most parodies of the Universal Frankenstein use this pose though, without bothering with the reason why.

Literature

 * In The Bobbsey Twins, Freddie suffers a bout of Sleepwalking where he gets up and stands in front of Flossie's bed, making her think there's a ghost.
 * In Heidi, Heidi starts sleepwalking in Frankfurt as her health fails due to homesickness.
 * A plot point in The Moonstone.
 * In Dracula, Lucy is a chronic sleepwalker who sleepwalks all the way across Whitby to the cemetery overlook the night she's first bitten by the eponymous vampire.

Live Action TV

 * On ANT Farm, Olive does this during a slumber party. While sleepwalking she makes rooster noises, plays golf and sleep-knits, and isn't aware that she sleepwalks.
 * The Drew Carey Show had the title character sleep-eating.
 * In House, one of House's clinic patients was a women who got pregnant because she had sex with her ex-boyfriend while sleepwalking.
 * Another patient was a sleepwalker who went as far as to buy cocaine in his sleep.
 * An episode of Law and Order Criminal Intent had a sleepwalking cop as a suspect.
 * In Desperate Housewives, Orson's guilt over eventually causes him to sleepwalk while muttering apologies. For added embarrassment, he sleeps in the nude...
 * On Happy Endings, Max accusses Dave of eating his food while asleep, so he sets up a video camera to catch him in the act. Turns out Dave does sleepwalk,

Music

 * They Might Be Giants has the song "Sleepwalkers", which is about, well, what you'd expect, and references the "arms held out, eyes closed" thing.

Video Games

 * Two moves in Pokémon, Snore and Sleep Talk, both of which allow the Pokémon attack while under the "Asleep" effect.
 * Amos from Dragon Quest VI turns into an enormous monster while sleeping, and doesn't know about it.

Western Animation

 * Ed, Edd n Eddy: one episode had Ed sleepwalking and sleepeating.
 * There was an episode of Rugrats where Stu sleepwalks and the babies believe he is a robot.
 * An episode of Hey Arnold dealt with Phoebe trying to stop Helga from sleepwalking to Arnold's house.
 * In one episode of The Powerpuff Girls, Professor Utonium, after being overworked in the lab, starts sleep-shoplifting.
 * Wilhemina Packard from Disney's Atlantis the Lost Empire is said to sleepwalk, though we don't see her do it. The fact that she sleeps in the nude probably has something to do with it. The other characters wear sleep masks because of this.
 * In Rocko's Modern Life, Ed Bighead experienced his childhood trauma of pirates when watching a play. He begins sleepwalking on his roof as a pirate in search of a treasure map.
 * In The Flintstones, Wilma states that every time Fred goes on a diet, he sleepwalks to the fridge.
 * On Family Guy, Stewie observes Joe sleep-dragging.
 * Olive Oyl sleepwalks in the Popeye the Sailor cartoon "A Dream Walking", while Popeye and Bluto frantically try to keep her safe.
 * Homer Simpson starts sleepwalking under the effects of sleeping medication Nappien. Bart takes advantage of the situation and uses Homer as his personal "zombie".

Real Life

 * Homicidal somnambulism -- an extreme form where a sleepwalker commits murder while asleep.