Mysterious happenings are causing major trouble at Horace Hotwater Middle School! Sam Gibbs and his super-strong tiny buddy, Hammie Rex, keep encountering creepy abnormal objects, including a floating sports jersey and a runaway go-kart. Sam doesn't believe in ghosts, but he has to admit the hauntings are getting weirder-- and more dangerous. Could bizarre mutant animals be the cause?

Sequel to: Hamstersaurus Rex vs. Squirrel Kong.