"Hey uh, about that puppet thing, uhh, There's some weird thing where..uhh.. that puppet thing is, it looks like a doll, Apparently..he appears.. if uh... you don't wind up the music box...So...be safe." Phone guy describing The Doll in the Night 2 phone call in the second game.
The Doll is a character that is involved with the events of Five Nights At Freddys 2, The Doll is an animatronic that was with the puppet, the employees were unsure but they still took it there anyways, and it wasn't a smart choice, as now there is 2 things to worry about in the Prize Corner feed. Apparently The Puppet made The Doll to distract the player while the puppet is coming for you, Nothing else is really known.
The Doll stays in the prize corner camera all of the time, meaning he never moves.
The Doll is an animatronic that never moves, but distracts the player, Whenever you forgot to wind the music box, You can hear Doll laughing and giggling, covering the sound of the pop goes the weasel song, also, Whenever the music box is about to run out, doll will most likely quietly giggle and disable the warning for 5 seconds, making you're job much harder.
The Doll looks like The Puppet a bit, he has a black mask and the puppet has a white mask. Doll is a very short and small gray humanoid looking animatronic with a black mask, looking almost exactly like the puppets, but the cheeks are purple, and its face is black, The eyes and mouth also look a bit different, as they are just white holes.