Jackalope

Jackalope are creatures from the Earth Kingdom, they appear in Appa's Lost Days.

Anatomy
The Jackalope has a small body of a regular rabbit, however, unlike a rabbit, the Jackalope has two large antlers on its head.

Real World Connection
Other than Dragons, the Jackalope is the only mythological creature referenced in the show.

Trivia

 * Since the animal is seen only once, it can be safe to assume that it is either rare or endangered.