10 Great Supervillains With Terrible Origin Stories
4. Onslaught Is A Long Story
On one hand, Onslaught has a badass design, serious skillset, and interesting creation story. On the other, he's a psionic entity made when Professor X and Magneto melded minds, and he attempts to use Xavier's crush on Jean Grey to turn her evil.
This is both the single dorkiest evil plot of all time to be pulled off by a creature that isn't evil technically real, and also took the one plot line we all desperately, desperately wanted to have been retconned - that is, for Xavier to be in love with a woman who he more or less raised from being a child, and who he is a father figure to - and showed it can still canon, which sucked on several levels.
Onslaught is a cool as hell concept, but there must have been better ways for it to have been pulled off than having Magneto and Xavier fuse Dragon Ball style and then for the resulting psychic energy baby to hang out in Professor X's head for like thirty years.