Springtrap, or Spring Bonnie, is the main antagonist of the 2015 horror game, Five Nights at Freddy's 3 by Scott Cawthon. He is the only character in the game that will kill the player as opposed to just jump scaring him/her.
He also appeared in Five Nights at Freddy's 4, where he played a minor role as a mini game figure, and briefly in Five Nights at Freddy's: Sister Location during one of the endings to the Custom Night update.