There is, apparently, no secret animatronic in FNAF Sister Location, or one that the community has discovered.
The "secret" animatronic's name is Scribble Netty. (Seriously)
You click the McM place.
you need to save all the nights then go to a secret place then open the kep and you have to bomb him
Click on a book and it will open the secret door
Go into Arturus's castle and in the room with the robot mouse, the secret paper is on the chest by the bed.
Woozworld Is Awesome!
8pm monday nights on abc family
OPEN is the first answer
Secret is NOT the answer. The correct answer is "undetermined." A+
sex
u need to go to the castle and enter the left door.
It goes through a secret passageway in between 2 stacks of hay