Two-Face's Coin

With some variations in different incarnations, after Harvey Dent, the lawyer prosecuting mobster Sal Maroni, is splashed in the face with acid he becomes Two-Face, he takes Maroni's lucky double-headed coin. Most famously, Harvey Dent uses a two-headed silver dollar, one side of which is scarred, the other side clean. Flipping the coin dictates Harvey when making any significant life decisions. If the coin lands on the scarred side, Two-Face will pursue acts of evil. If the coin lands on the unmarked side, he is compelled to commit acts of good. At one point Dent as Two-Face was so dependent on the coin for any of his criminal acts that he could be easily defeated by taking the coin away from him or preventing him from seeing the result of the flip. Harvey Kent (Earth-Two) was usually shown at this level of dependency. Dent has since lessened his dependency on the coin flip to whether a situation should be implemented, rather than each individual act.

Batman Forever
Two-Face's signature coin appears in Batman Forever. Batman easily defeated Two-Face by throwing up multiple quarters and silver dollars while the villain was in the middle of flipping his coin.