People are very vulnerable creatures when they're asleep. Their defenses are down, they usually feel like they're in a safe place. Thus when someone is killed in their sleep, it's portrayed as someone being killed when they're at their most defenseless. Doing so is often the modus operandi of the Dirty Coward, who would be afraid to kill someone when they can fight back. It can also be used as Paranoia Fuel, as everyone has to sleep at some point, thus everyone (even the viewer) is vulnerable at some point. Often subverted by the killer stabbing a Sleeping Dummy.
This trope is often combined with Vorpal Pillow (since it needs the target to be immobile with their face exposed). This may also be done by a Dream Weaver in cases where Your Mind Makes It Real or the person's dream experience in some way influences the body. This is also one of most frequent uses of Animal Assassin, as getting an animal to attack an active moving person is just plain difficult.
Subtrope of Kick Them While They Are Down.
Not to be confused with its Sister Trope, Passed in Their Sleep, where someone's death during sleep is portrayed as peaceful and one of the best ways to go. Any examples where a character is injured, falls asleep, and dies from the injury while asleep go there. This is for when characters are targeted when they're asleep.
Since this is a Death Trope, beware of spoilers. There will be unmarked spoilers on this page.
- An early episode of Mobile Suit Gundam Wing has Wufei attack a military academy during a nighttime raid, blowing up the barracks while most of the cadets were asleep. This incenses the remaining crew on the base, considering it a dirty tactic. Ironically, Wufei is one of the most honorable people in the series, but he considered his mission more important than his honor.
- In Sword Art Online, it's mentioned that the dueling rules permit Player Killing even in safe zones; one thoroughly vicious trick is to manipulate a sleeping player into agreeing to a duel via the in-game interface and then murdering them with impunity.
- Detective Conan has more than one case where the victim is attacked while they're sleeping. i.e, in a case where Ran is the target for being a potential Spanner in the Works, the killer attacks her when she and Conan are sharing the same bed. Conan manages to wake her up right before the murderer chops her with their axe, however.
- Subverted in another case, where the culprit tried to kill a teenager in the kid's sleep... but they only stabbed a mannequin that the police had placed there, betting that the killer would try finishing their job.
- In an early episode of Noir Kirika and Mireille have taken a contract in an unnamed Middle Eastern country to kill a powerful warlord and Kirika approaches his bed and shoots him while he's asleep. Except the first shot either didn't do the trick or he wasn't actually asleep at the time, and as she turns away he manages to get off a shot that hits her in the side before she pumps several more into him just to be sure, kickstarting the plot of the rest of the episode as they struggle to escape the country with Kirika wounded.
- In Avatar: The Last Airbender – The Promise, Zuko mentions multiple attempts to assassinate him while he's slept.
- Carter Blaine in the first volume of Resident Alien was murdered with a knitting needle while he was asleep.
- Hyacinthe in Dungeon: The Early Years slit the throats of all of his enemies in one page when they are sleeping in the fifth tome "Not A Sound". It's the final step of Hyacinthe dropping his ideology of knighthood and accepting his current status of kingpin.
Hyacinthe: Thank you, but I think I'll settle this the modern way.
- Satan himself is killed like this in Hellboy. By Hellboy. And he's not even sure why because he can't remember doing it.
- The Nightmare on Elm Street series has this "Cause of Death" for Freddy Krueger's victims.
- Tommy Ray is a psychic being trained as a dream assassin. He can enter other people's minds while they're asleep and kill them in their dreams, which causes them to die in real life as well. Early in the film he does this to kill a woman he's supposed to be trying to help.
- At the end of the movie The Hero Alex does the same thing to the Big Bad to end his threat.
- Grosse Pointe Blank has the main character (a hitman) attempt this via poisoning, but he botches the mission and has to shoot the now awake target.
- In Star Wars Episode III: Revenge of the Sith Chancellor Palpatine relates to Anakin Skywalker the tale of Darth Plagueis, who had such fine control of the Force that he could use it to influence the midi-chlorians to create life. He taught almost everything he knew to his apprentice, who then killed him in his sleep. (In the Star Wars Expanded Universe and the still-canon StarWars.com encyclopedia, it's explained that Palpatine himself was the apprentice in question.)
Palpatine: It's ironic. He could prevent others from dying, but not himself.
- Here's a diorama that depicts how the deed was accomplished. (Warning: Only those with strong stomachs need click.)
- In the film version of You Only Live Twice James Bond's girlfriend Aki is murdered in her sleep by mistake (they were aiming for Bond). An assassin sneaks into the rafters of their bedroom and lowers a string, then puts a drop of poison on the string to drip down into Bond's mouth; but Bond and Aki both turn over, so poor Aki's mouth is where the string is.
- The Lord of the Rings: The Fellowship of the Ring: Subverted. We see the Nazgul stabbing what seems to be the Hobbits sleeping in their beds, to death. But the Hobbits had filled their bed with straw to make it look like they were in bed, and were hiding somewhere safe.
- In Agatha Christie's books:
- In And Then There Were None, the second victim was Mrs. Ethel Rogers, who died in her sleep from an overdose of chloral hydrate. This is because she showed regret for the crime she and her husband commited in the past, so the culprit decided to kill her painlessly - the husband didn't share such guilt, so he was murdered in a much more bloody manner.
- And in Curtain Hercule Poirot drugs Stephen Norton with the sleeping pills in his hot chocolate, then carries him to his room in disguise, sets him on his bed, and fatally shoots him in his sleep so that he may never manipulate any more people into killing each other again.
- Death on the Nile has the victim shot through the head while asleep.
- The matriarch in Towards Zero is killed while asleep.
- In the first book of the X-Wing Series, Imperial forces attacking Rogue Squadron's base in the pre-dawn hours when only a few were awake got into a firefight in one of the barracks where one of the Rogue pilots was killed before having a chance to wake up. It was later revealed to be Lujayne Forge, who was becoming something of the group's Team Mom. The Rogues took her death pretty hard, not only because of that, but because they felt she had been murdered in her sleep, rather than killed in honorable combat.
- Defied in one of the Mage Storms books. A major character is a trained assassin. Some other characters think he doesn't sleep much because of a guilty conscience. The real reason is that as a trained assassin, he knows how easy it is to kill a sleeping person.
- Played for Laughs in several Discworld books where "soon we shall all be murdered in our beds" is used to identify the speaker as a petty, xenophobic and narrow-minded citizen (since it usually involves foreigners to Ankh-Morpork). In Jingo, a very old lady uses the variant "when Klatchians will be ravishing us in our beds", to which Carrot of all people responds "those Klatchians are mighty brave".
- The Lord of the Rings
- Averted by the hobbits in J. R. R. Tolkien's The Fellowship of the Ring, who had stopped at the Prancing Pony Inn and had gone to their rooms for the night. Some Bree-men suborned by the Ringwraiths gained access to the hobbits' room, where attacked what they thought were the hobbits in their beds. Fortunately, Strider had forewarned the hobbits about this; what actually happened was the ruin of several good bolsters.
- In Return Of The King, Saruman suspects that his servant Grima stabbed Lotho Sackville-Baggins in his sleep.
- It's mentioned in Sword Art Online that this was a common method of player-killing in SAO; ordinarily players had to agree to any Player Versus Player fights, but PKers would sneak up on someone who was sleeping, challenge them to a duel to the death, then lift the other player's hand to push the menu button to accept the challenge.
- In The Way Of The Tiger Avenger almost does this to Honoric who only survives through divine intervention.
- In the Story Within a Story "The Tale of the Three Brothers" from Harry Potter and the Deathly Hallows, the eldest brother is murdered in his sleep after boasting about how his wand, the Elder Wand, is undefeatable. This shows his folly in trusting the Elder Wand since he can still be killed outside of duels.
- The Worm Ouroboros: When general Corsus believes his soldiers plan to mutiny and put Gallandus in his place, he stabs Gallandus to death in his sleep.
- The Saga of the People of Vatnsdal: Hidden in the house of the highwayman Jokul, Thorstein Ketilsson is so impressed by Jokul's size that he does not dare to attack him until he is fast asleep in his bed. He then skewers him with a sword so "that the sword-tip was stuck in the bed."
- MythQuest. Mosaku goes to sleep after telling his apprentice about An Ice Person named Yuki-Onna who lives in the woods. While he's asleep, she comes and sucks his life out, and he doesn't wake up.
- One episode of CSI: Miami had the Victim of the Week die in her sleep at the pool of a luxury hotel when the killer hid a silenced pistol in a stack of towels and went down the line dropping them off, except when he got to her, at which point he put a bullet in the back of her skull then went on without anyone nearby realizing what had happened.
- Stargate Atlantis: The team finds an Ancient warship adrift in deep space with a crew that has been in stasis for 10,000 Years. When they board, they find a Wraith has also gotten onboard, killed one of the slumbering crew and taken her place, tapping into the crew's mental network to try and find out what secrets the ship holds.
- Rick's group in The Walking Dead pull a particularly nasty version when they invade The Saviors' compound.
- Babylon 5: Alluded to in this exchange after Londo demands to know why a Narn ship at the station won't just open fire on a Centauri ship:
Garibaldi: It’s the same guarantee I gave that none of the Narns would break into your quarters in the middle of the night and slit your throat.
Londo: Mr. Garibaldi, you have never given me that promise!
Garibaldi: You’re right. Sleep tight.
- Classical Mythology
- The giant Argus had one hundred eyes all over his body and it was said only about half of them closed when he was asleep. Hermes lulled him to sleep with his music and songs, until all of his eyes closed, then decapitated him.
- Perseus decapitated Medusa in her sleep.
- Norse Mythology:
- "Reginsmál" in the Poetic Edda specifies that when Fafnir murdered his father Hreidmar because of Andvari's gold, he did so by stabbing him in his sleep.
- Völsunga saga: Intending to murder Sigurd, Gutthorm sneaks into Sigurd's bed chamber, but backs down twice because Sigurd is not fully asleep. Only when he finds Sigurd sound asleep, he dares to run him through with a sword.
- The Saga of Ragnar Lodbrok: Urged on by his wife Grima, Aki murders their guest Heimir by striking him with an axe while he sleeps.
- Jim Steinman's "Love And Death And An American Guitar" has the narrator boast of killing his parents in their sleep (under the influence of the Guitar).
- The Doors' "The End" has the same theme: James Morrison raps on sneaking into his siblings' and parents bedrooms and...
- One of the murders committed in The Beatles' song, "Maxwell's Silver Hammer", could have been this.
- William Shakespeare was fond of this trope in his plays, especially when someone was being assassinated.
- Macbeth murders King Duncan in his sleep with a dagger (after getting his guards drunk so he can blame them for it). For this, Macbeth is cursed with insomnia.
- In Hamlet, Claudius murders the old king (his brother) in his sleep by pouring poison down his ear.
- Antonio and Sebastian attempt to do this to King Alonso and his adviser, Gonzalo, in The Tempest. Gonzalo is awakened by Prospero's spirit, Ariel, and prevents the murder.
- The Legend of Zelda: Breath of the Wild allows Link to perform insta-kills on any sleeping enemy.
- Invoked by Helena Chang at the end of Dreamfall: The Longest Journey: while Zoe Castillo is asleep, saving the world with her dreams, Helena injects her with an overdose of hallucinogenic drugs that put her in a coma from which she isn't supposed to awaken. As Dreamfall Chapters shows, however, even that OD couldn't prevent Zoe the Dreamer from waking up.
- The Deadly Reflex mod for The Elder Scrolls IV: Oblivion alters fights by adding several new combat moves. One of them allows you to perform an One-Hit Kill attack on any sleeping NPC if you are sneaking. Doing it on a neutral or friendly NPC is considered as "murder" by the game's stats.
- In Fallout 3, Fallout: New Vegas, and Fallout 4, the Mr. Sandman perk gives you the option of automatically killing sleeping NPCs instead of pickpocketing them. Fallout 4 changes the 50 Experience Points to +15% for every sneak attack with a silenced weapon (meaning guns only) and goes up to +30% at level 17 and +50% at level 30.
- Defied by the Reapers of Mass Effect. It's theorized by several parties that the Reapers hibernate in the Dark Space between the Milky Way and other galaxies. They choose this location because there's little chance of being stumbled upon by other species and destroyed while in their most vulnerable state.
- Can be invoked by the player themselves in many Role-Playing Games. If a player is rather overleveled and puts an enemy to sleep, they could easily bypass the "wake up when hit" rule by one-shotting them. Games with a Back Stab feature usually use it when performing a surprise attack on a sleeping character.
- In Dwarf Fortress, attacks made against unconscious targets always accurate, and hit with maximum solidity. In an exception to the relative randomness of AI attacks, they will always aim for the head when attacking someone that's out cold. Even if the target has a good enough helmet on.
- King's Quest IV: Rosella shoots Lolotte in the chest with a love arrow while the wicked Fairy is asleep. It wasn't intentionally lethal, but Love Hurts Evil.
- King's Quest VI: Abdul Alhazred, after scheming for years, gets Princess Cassima out of the way by having her abducted by a fellow member of the Black Cloak, and then stabs the King and Queen to death in their bed, making him the unchallenged ruler of the Green Isles. when Cassima came back, he invoked a dated mourning tradition to keep her imprisoned and planned a Sham Marriage to cement his position, and then kill her after the wedding night. The only Spanner in the Works was the Prince of Daventry showing up with a crush on the Princess.
- In Overwatch, Overwatch agent Gérard Lacroix was killed in his sleep by his wife Amélie, who had been turned into a Manchurian Agent by the Talon terrorist organization after they abducted her, suppressed her personality and broke her will and then arranged for her to be found by Overwatch agents and returned to her normal life apparently none the worse for the wear. Once her programming activated she returned to Talon and became the assassin Widowmaker.
- Many Shin Megami Tensei games have the Sleep status effect. Some of these games also have the spell Eternal Rest, which instantly kills any opponents who are asleep. And yes, this being SMT, there are enemy demons who will exploit this by having both sleep-inducing spells and Eternal Rest.
- Metal Gear Solid 2: Sons of Liberty lets you tranquilize guards, putting them to sleep without you being discovered. If you feel extra cruel, you can shoot them in the head while they're sleeping.
- The Adventures of Dr. McNinja: During his time in a vigilante club, Doc and his club members were attacked by assassins after once of them sold them out. Doc fought off the attackers in his sleep. His friend James wasn't so lucky.
- In the Justice League episode "Only a Dream", Dr. Destiny kills his wife in her dreams and then attempts to murder the League. This is shown to be very brutal, as he essentially tortures her in her sleep until her body can't take the strain.
- In The Legend of Korra Suyin attempted to assassinate Kuvira in her sleep. Unlucky for her it was a trap. Kuvira had seen this coming and used a double. Suyin and her gang end up captured.