Caliban

Caliban made a number of cameo appearances in X-Men, including the episode Slave Island. He also appeared in the final season episode The Fifth Horseman, in which Caliban had been transformed, being given superhuman strenght, by Fabian Cortez into one of Apocalypse's Hounds (used in a similar role to the Horsemen), who sought out a mutant to use as a new host body for Apocalypse's reincarnation. When Jubilee was selected as the new host, Caliban turned against Cortez and the rest of the Hounds. In consequence, Cortez stripped Caliban of his strenght.

Powers

Caliban's mutant power allows him to psionically sense other mutants out to several miles and track their movements. Cortez made him bigger and gifted with superhuman strenght.

Trivia

At some point in The Fifth Horseman, Caliban was mentioned to having been a member of the Morlocks, though he had never appeared in the episodes featuring the underground mutant community.

Also, in the same episode, is implied that Caliban had met Jubilee before, and that's why he turns against Cortez. At which point they met is unknown, but it could have been when they were both imprisoned in Genosha in "Slave Island" or he could have been with the Morlocks offscreen in "Have Yourself A Morlock Little X-Mas", when Jubilee went to the Morlocks' tunnels.