"Mad" Jim Jaspers is a powerful supervillain from Marvel comics who was an enemy of Captain Britain and Excalibur as well as a few other heroes - despite his relative obscurity he is considered one of the most powerful mutants in existence, two versions of him existed and the most powerful one is the Earth-616 version (which is the mainstream Marvel Earth). His power can be summed up as so: the less powerful alternate-reality Jaspers was so dangerous his entire reality had to be erased to get rid of him: the more powerful mainstream Jaspers threat is so great that Merlyn has suggested he could become an Omniversal threat (which means he could theoretically become dangerous enough to destroy/take over entire multiverses): his current level of power after several defeats is unknown.