|“||That rabbit's foot ain't no dime store notion. It's real hoodoo; old world stuff. Made by a Baton Rouge conjure woman about a hundred years ago. (...) It's not a luck charm; it's a curse, she made it to kill people, Sam! (...) See, you touch it, you own it. You own it, sure, you get a run of good luck to beat the Devil. But, you lose it, that luck turns. It turns so bad that you're dead inside a week.||”|
The Rabbit's Foot is a cursed object which can give anyone who touches it incredibly good luck that eventually turns bad when it is lost.
The rabbit's foot was apparently made by cutting it off a rabbit in a cemetery, under a full moon, on a Friday the 13th. At some point, it ended up in the possession of John Winchester who kept the rabbit's foot in a curse box in his lock up.
The rabbit's foot was eventually stolen at the behest of Bela Talbot who wanted to sell it on the black market and learned its location from spirits who had fallen victim to its power. However, Sam and Dean Winchester were able to get their hands on it and Sam fell under the rabbit's foot's power and later curse after Bela stole it. Dean managed to retrieve it and used the rabbit's foot's power to defeat two hunters who had cornered Sam.
To break the curse and save Sam, the Winchesters performed a ritual discovered by Bobby Singer that could destroy it. Though Bela tried to force them to hand it over, Dean tossed her the rabbit's foot, causing Bela to fall under its power. With no other choice, Bela helped destroy the rabbit's foot and break the curse.
Twelve years later, Dean compared the rabbit's foot to the coins at Fortuna's pool hall when Sam stated that he'd originally thought the coins and the varying luck involved were due to a curse.
when Sam had it, two people he was fighting knocked themselves out by accident and when Dean had it, no bullets could touch him despite the close range. However, the catch is that if someone inevitably loses the rabbit's foot, the luck turns bad and they die in the next few days, unless they reobtain it to turn their luck around again. Apparently, the only thing the foot doesn't raise one's luck at is the current owner's chances of keeping the foot in his or her possession indefinitely.
The curse can be broken by destroying the rabbit's foot - the ritual involves burning it in a cemetery with bone ash and cayenne pepper.