Pipsqueak

Pipsqueak is a minor character in My Little Pony: Friendship Is Magic. His only major role was in "Luna Eclipsed", but since then, has made background appearances.

As Skippy in Kovu Hood
He is a rabbit

As Flounder in The Little Cardinal
He is a fish.

As Timothy Brisby in The Secret of NIMH (Nuclearzeon Animal Style)
He is a mouse.

As Young Thumper in Bagheerambi
He is a rabbit.