Goozim

A goozim is a large, brown, hairy seemingly carnivorous mammal native to Druelselstein.

Goozims apear to be dangerous but capturable as a game in Druselstein called poke the goozim with a stick shows one locked up and being poked by Mr. Doofenshmirtz, its actual shape is undefined as in its only cameo it was locked up in a small square cage causing its shape to become that of the cage, also the cage was not very strong looking implying that goozims may be weak for thier size.

They may be an allusion/parody of the many strange creatures in dr.suess books.