Leonard (X-Files)

Leonard is the main villain the The X-Files episode "Humbug" and was one of the show's many "monsters of the week" that helped to gain the show's cult status - the episode itself is known for being one of the more comedic in the series despite dark tones and violence, most of which came from Leonard and his murderous ways.

History
TBA

Abilities
Leonard is a mutant that can detach from his conjoined twin, Lanny, at will and go on vicious murder sprees, trying to burrow into victims - it is even suggested near the end of the episode that Leonard is immortal and somehow living inside the Conundrum despite being eaten alive.