"Mutant" means change, and there was plenty of that when the Uncanny X-Men counted down to the Marvel Mutant Massacre, beginning with the trial of Magneto! Rachel Summers became Phoenix and the Brotherhood became Freedom Force! Lady Deathstrike became a cyborg, Moonstar a Valkyrie, Colossus a killer, and Psylocke an X-Man! And Sabretooth first set his clawed food into the X-Universe alongside his fellow Marauders! Guest-starring the original X-Factor,Power Pack and Thor! Gods, Morlocks, talking frogs and more!