It isn’t explained AT ALL, but for some reason, throughout the course of this battle with the Marauders, the Uncanny X-Men become enchanted and corrupted by the demon Inferno from Limbo and they all turn wicked. It doesn’t really make any sense because as we’ve seen during this massive crossover, nearly every superhero from the Marvel Universe is out in the streets beating back the invading demon army, including X-Factor and the New Mutants, the X-Men’s mutant counterparts, and yet only the X-Men turn murderous and evil. But regardless of the reason why, I absolutely love this plot twist. Each evil member of the X-Men looks completely bad assed, as their faces turn black, their clothes rip apart, and their hair and masks turn into the visages of demon horns. Such an awesome element to an already creepy story. This would make such a good movie. Also, that "trouble" Wolvie just got a wiff of? Welp, that's only a hint at the biggest confrontation I've been waiting for ever since Jean died. (Uncanny X-Men #241 – Feb 1989)