Perseus is Deuce Gorgon's grey pet rat.
Perseus is a grey, pot-bellied rat with an orange mowhawk and stomach, an earring in one of his ears, brown eyes and two tails.
"...Named for an ancient Greek warrior mom knew. She doesn't think it's funny."
- Perseus is named after the warrior of the same name, but in myths, Perseus was the one who slayed Medusa, though Medusa wasn't slain in the Monster High franchise. Deuce himself mentions that his mother doesn't find it funny.
- Perseus has a piercing just like Deuce on his left ear, and a fingerless glove that also matches his owner's.
- Rats and mice will eat just about anything, not just cheese.