sentences:  By then she had completely decomposed to a skeleton.Illyana, facing a rebellion of Limbo's demon population that threatened to overrun Earth, smashed Cat's skull in rage over the demonic taint that Belasco left on her soul and frustration over the horrible choice she had to make to kill Cat.Kitty is briefly shown in the background as a zombie in "Ultimate Fantastic Four" #23, despite her mutant phasing powers.