Uncanny X Men Annual #14 by Chris Claremont

A time-lost adult Franklin Richards appears in the present, unleashing reality-warping echoes of the past that draw together the X-Men, X-Factor, and the New Mutants, even as Ahab and his Hounds try to enslave heroes to hunt mutants. Rachel Summers is forced to confront her history as a Hound while the combined teams battle to free their captured allies and protect the younger Franklin from his future self. The crisis ends with the adult Franklin accepting his paradoxical existence and fading, Ahab retreating into the timestream, and the heroes left wary of the timeline’s fragile balance.