The Plush Animatronics were added to Fredbear's Family Diner in 1975 being the first animatronics added that did not have a "Spring-Lock" capability. This is due to their obvious small stature.
They were created to sell more merchandize at the location getting a completely custom stage next to formerly Fredbear and Bonnie.

The Plush Animatronics were known for being quite fast and wandering the Pizzeria often to interact with children. However due to the parameters of the pizzeria not being set very well they do have the ability to crawl through vents.

It is well known that the Plush animatronics can give quite the fright if they sneak up on you but no harm can come from them. Still it's best if you keep your distance.