Wooden Stake

""..Dis is my lucky stake. I have killed many vampires with it. I call it Mr Pointy.""

- Kendra, Buffy the Vampire Slayer

The favorite (and generally speaking, only) weapon of the vampire slayer. Because weirdly enough, only wood can kill a vampire, whereas sword impalement short of beheading cannot. This may be because the wooden stake was a once living plant, much like the vampire was a once living human, unlike the sword which was never alive. Yes, this frequently means that someone can be killed via pencil to the heart.

In early vampire fiction -- and before that, in vampire legends and folklore -- stakes were simply used to pin a "vampire" into its coffin while it slept, keeping it from waking back up and causing trouble. (Actually killing one was a far more complicated process, usually involving Communion wafers, decapitation and burial at a crossroads.) When it became a bizarre all-purpose vampire-killing weapon is unclear.

Film

 * Surprisingly, the original film version of Buffy the Vampire Slayer didn't have the insta-kill stake -- as evidenced by the need to burn vampires, and Pee Wee Herman Amilyn's extended death-by-wooden-ruler throughout the closing credits.

Live Action Television

 * Unlike its film predecessor, the TV series of Buffy the Vampire Slayer implemented the stake-o'-death.