Mr X is an anthropomorphic dog.
This wild-haired ball of nerve is a genius inventor and fiendish criminal. X has never been caught and identified, thanks to his constant inventions always getting him out of the police's reach at the last minute. X lives on a floating castle, where his assistant is a trained monkey called Kilgore. X considers the Phantom Blot to be his only friend.
Behind the scenesEdit
Mr X first appeared in the 1964 story The Phantom Blot Meets the Mysterious Mr X.