The Bunny Children are a large group of anthropomorphic rabbits.
These Bunny Children of absurdly high numbers are the offspring of Oswald and Ortensia Rabbit, and now live in Wasteland along with their parents. Growing up in a land of magic and adventure has apparently done wonders for them, as they are capable of holding their on in battles against Blotlings. The flip-side of this independence is that they tend to scatter and run off on their own without listening to any grown-ups… and with some counts putting the number of identical bunnies at 420 or more, it's all but impossible for Oswald and Ortensia to keep full track of them.
Behind the scenes
The exact numbering and gender of the Bunny Children is unknown. A Hole in the Sky (taking place a substantial amount of time before the Thinner Disaster) states that Oswald and Ortensia have 420 children, and imply that all of them are named Oswald Junior the [N]th, by order of birth, suggesting they are all boys. However, Epic Mickey 2: The Power of Two shows Oswald and Ortensia's 101th child to be a girl.