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 slayed 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 don't actually like cheese. This is a common misconception. They'll eat it only if there's nothing else to eat. This is thought of how mice were thought to like cheese.