Austin's cat is an unseen pet, supposedly belonging to Austin.
In "Whodunit", Mr. Austin Frothingslosh claims that he needs to feed his cat. He mentions that the cat is female, that he recently got her, and that she is almost always hungry. Detective Pablo is skeptical of the cat's existence.
It is unknown what Austin's cat looks like, as she has never been shown.
Austin's cat has not appeared in any episode of The Backyardigans. However, the animal was mentioned in "Whodunit" from season two.