One of the Morlocks killed during the Mutant Massacre by the Marauders, Lightning Bug had the ability to leave its body via telepathic projection. When its body was killed it sought a new body, coming into contact with Jean Grey. Taking the form of the Phoenix Force, it brought her to its resting place, hoping to take her form. Fighting back, Marvel Girl destroyed the ash pile covering Lightning Bug's body, allowing Lightning Bug to finally perish.