The Alligators are a trio of characters that only appeared in the 1927 cartoon Oh What a Knight. In it they are guarding the entrance to the castle that Princess Ortensia and Knight Pete live in (Read more about their role in the short; below). They eventually became forgotten and retired characters and were sent to Wasteland.
In Oh What a Knight
Oswald the Lucky Rabbit travels the world on board a donkey as a musician playing on the accordion. He comes upon a castle, which is defended by a moat filled with a trio of hungry alligators. Oswald's Steed (a donkey) accidently trips and causes his master and him to both tumble down the hill and fall right into the moat of alligators. Though Oswald manages to avoid getting eaten, his donkey isn't so lucky; despite surviving, his tail is eaten by one of the crocodiles, but soon pulls a new one with the donkey leaving and sarcastically leaving in proper order with his tail up.
The Alligators appear residing in Wasteland and one of its Projector Screen levels based off Oh What a Knight. They act as temporary platforms for Mickey to jump on, but will go under water and attempt to bite him.
Epic Mickey 2: The Power of Two
The Alligators now reside in Bog Easy, where they act in a similar fashion. Mickey can step on them, but many will rise up and snap at him as he tries to move across. The game also has some alligator set-pieces that can be thinned out and painted in.