Vorpal Pillow

In TV-land, suffocation is a quick and easy matter. You put a pillow over someone's face, they struggle for all of ten seconds, and then are dead. It's just that easy.

Works with strangling someone as well, though a person is more likely to survive being held by the throat. Drowning is also quicker than it'd likely be in reality, but it's not five seconds after you fall into the water, and even someone who was unconscious by the time they were reached will likely be revived easily enough.

A pillow over the face, on the other hand, will result in five seconds of struggling, followed by five seconds of squirming, followed by death.

This despite the fact that most pillows are quite porous and allow for some air to get through, so even if it were kept as tightly around the nose and mouth as possible (despite struggling and all) it would take quite longer for a person to die than if their air supply were entirely cut off.

Comic Books

 * Batman: Batman: Dark Victory - Alberto Falcone is killed by his sister Sofia in exactly this manner. Semi-justified in that Sofia is a very strong woman.
 * The "instant strangulation" trope is averted in the 2008 remake of The Unknown Soldier. The main character uses a makeshift garrote to quietly kill a Child Soldier and thinks to himself how it takes a long time to strangle a person, even a young boy. Even he's surprised, and he's a doctor.

Film

 * One Flew Over the Cuckoo's Nest
 * Subverted in Inglourious Basterds. Stieglitz smothers the SS' head with a pillow, but instead of suffocating him, he then pulls out his knife and repeatedly stabs the guy in the face through the pillow.
 * In a similar vein to the Inglourious Basterds example, Angel Eyes of The Good, the Bad and the Ugly puts a pillow over his employer's face, but then uses it to muffle the gunshots.
 * is killed this way in Blood and Black Lace.
 * In Talladega Nights, Cal tries to do this to end his friend's suffering. Since Ricky Bobby isn't suffering at all, just napping, he fights Cal off.
 * In Vanilla Sky this is mixed to a disturbing degree with Out with a Bang.
 * Esther does this to Danny in Orphan.
 * Subverted in Haywire. Someone gets pinned with a pillow over their head, and it looks like this trope is in effect, but the pinner's just catching their breath. They go for a gun a moment later, and use the pillow to muffle the shot and the splatter.

Literature

 * A Song of Ice and Fire has Daenerys Targaryen doing this to someone who has been rendered vegetative.
 * Ser Osney Kettleblack also does this off-screen to the old High Septon under orders from Cersei.
 * Done by to  in One Flew Over the Cuckoo's Nest, as a Mercy Kill.
 * Native Son features a particularly extreme version of this trope. Not only does the victim die from suffocation by the pillow, but the person killing her didn't even realize what he was doing. What's more, a third person in the room didn't realize what was going on because the sound of the smothering was so negligible.
 * In The Remittance Kid by J. T. Edson, one of the anarchists sneaks into a hospital disguised as a priests and uses a pillow to smother a wounded accomplice before he can talk to the police.
 * In The Mallorean, Silk does this to a number of people offscreen as vengence for the death of a fellow spy, in order to Make It Look Like an Accident. (He throws one guy out a window for the same reason.) Then he runs short on time and has to start using knives...

Live Action TV

 * Happened near the end of season eight of Smallville to a depowered supervillain.
 * Twin Peaks, Leland Palmer suffocates Jacques with a pillow in a few short seconds; granted, the man was already injured and in hospital, but it was an extremely quick suffocation nonetheless. Made all the worse by the fact that they referred to the act of smothering with a pillow as strangulation in the following episode.
 * Angel tries this on Wesley at one point, but it doesn't work. (Some fans speculate that this was deliberate; he could have killed Wes easily in other ways, but he was really just making a point.)
 * On the other hand, Giles pulls off a Vulcan nose-pinch grip to kill Glory's host.
 * In the episode before, Buffy also does this to Dawn during her Heroic BSOD dream.
 * Played with on Seinfeld: George is in the hospital and is in "so much pain" that he asks Jerry to end his life this way. Jerry says "You mean like this?" and puts the pillow over his face for a second, and George starts yelling.
 * In Nip Tuck, after a plane crash, Julia thinks that her mother is dying and euthanizes her with a pillow. It turns out not to be her mom after all. Whoops.
 * Subverted on Boardwalk Empire: Eli tries to kill a survivor of the woods massacre when he reappears, badly wounded, by smothering him with a pillow in a hospital. It takes a very long time, though, and Eli is clearly exhausted by the time prohibition agents come bursting in - with the survivor wheezing, but still very much alive.
 * Used in Weeds, after switching off the life support fails to have the desired effect. "Shane, get mommy a pillow."

Tabletop Games

 * In Pathfinder, Monks of the Empty Fist can temporarily add abilities to improvised weapons that would normally not suit the weapon. Thus you can use a literal Vorpal Pillow.

Real Life

 * Real Life: This has been stated to be a leading cause of crib death in infants, whether inadvertently or deliberately. In the latter case the weight of the pillow itself provides all the force necessary for suffocation.

Theater

 * Othello: this is how Othello kills Desdemona.
 * What makes this one strange is that Desdemona is able to deliver a brief speech afterward.

Video Games

 * James euthanizes this way in Silent Hill 2. May be justified since she was extremely terminally ill with what appeared to be a respiratory ailment, but this may vary, both for James and the player.
 * BioShock (series) 2. Eleanor, the victim, gets better, but she is technically dead long enough to damage you...
 * Project Zomboid Bob can kill his injured wife with a pillow as a way to escape the tutorial, but not before giving one of the most tear jerking last words ever.
 * Hitman Contracts has one mission where you can kill one of your targets using a pillow. Amazingly, the rather long and loud struggle does not wake his wife sleeping next to him.

Web Comics

 * Averted in Dominic Deegan - when a pillow is used (backed with a spell that makes it cling to the victim's face) it chokes the attacker unconscious but, removed in time, causes no further damage.

Western Animation

 * Barney doing it to Homer in The Simpsons in a spontaneous parody of One Flew Over the Cuckoo's Nest. It does nothing and the characters are kind of confused by it.
 * In the episode of The Simpsons which parodied the life of Henry the 8th, Homer is killed very hastily and very cleanly this way by Marge.
 * Homer also does this to one of the recurring aliens in a Treehouse of Horror episode.
 * Family Guy: Peter imagines doing this to Lois in one episode. He doesn't actually do this to her though.