Mojo is one of the most disgusting and vile looking villains in the MU. He is part of a race of Spineless Ones and resides in an alternate universe he calls Mojoverse. Mojo has a long history of battling the X-Men, and has a special relationship with one member, Longshot, in particular.
The Spineless Ones were slowly driven insane by waves of energy which came into their dimension from the normal Marvel 616. Apparently these were television programs which became like nightmares to the creatures. Mojo became a producer and televised events throughout space that received huge ratings. Many of the people who were on the shows were either creations of Mojos, slaves, or kidnapped heroes.
Several times, people have revolted against Mojo, including Longshot, and the X-Babies and Baby Avengers. Both of those groups were created by Mojo, but apparently kept their strong moral codes. I’m not sure if those are supposed to be the same babies that Skottie Young used several times on covers, but they might be.
Mojo’s biggest impact on me was from the X-Men cartoon of the 90s. In it, he does what he does best. He is a evil producer who will stop at nothing to increase his ratings. He also was the central villain for one episode of Avengers Assemble, which shows that people still care enough about him to put him out there.
Is he the most interesting? No, not by a long shot (get it?). But he is different and that makes him special to me.