Wampus Cats

Wampus cats are a mythical species mentioned in Krakens and Lies.

Description
While wampus cats aren't explicitly described, it can be implied that they look like a cat, and are strong, as they are hard to wrestle.

Krakens and Lies
Zoe Kahn remembers that Matthew Kahn once drank a kale and raw egg smoothie every day because the Trackers at Camp Underpaw jokingly told him it would make him strong enough to wrestle wampus cats.

Trivia

 * Wampus cats are one of the mythical creatures not described in Camp Underpaw's Guide to Mythical Creatures, along with barangs, bunyips, deflectors, elves, enormous talking cockroaches, grindylows, monster spiders, pixies, scarabs, tooth faeries, vampires, werecreatures (besides werewolves), and will-o'-the-wisps.