Rex is a very large reptilian doglike creature found only in the world Tempest Peak Manor. His master, known as the Storm Giant, has been sucked away to the Shadowrealm 700 years ago, and he hasn't been fed since. Don't make yourself his next meal.
He is very fast and constantly follows Vexx throughout the manor. Fortunately, as long as Vexx remains above the floor, Rex has no way of getting to him. If he does fall, the he must get to an air vent as soon as possible, which will carry him up to where Rex can't reach. Fighting him is pointless, as he's invulnerable. Even in Fury Mode, it's impossible to kill him. It is, however, possible to outrun him if Vexx repeatedly uses his talons to propell himself forward.
Rex is a greenish reptilian about the same size as the Leviathan from The Below, with a sandy yellow underbelly. He has doglike ears, spines on his back, big yellow eyes, and a large drooling lipless mouth with big yellow teeth. He has two large legs with blue spots which end with huge feet, each with two toes tipped with very sharp claws. He's apparently armless and wears a collar with spikes and a bell on it.
- Although he can't be defeated, Vexx can still earn points from hitting him. However, this is risky and Vexx will most likely get eaten anyway.