Mutant Massacre

1986

The Marauders, led by Mr. Sinister, slaughter the Morlocks in the tunnels beneath New York City. Multiple X-teams are drawn into the conflict with devastating consequences. Angel's wings are destroyed, Colossus is critically injured, and the X-Men and X-Factor clash before discovering they're on the same side.

6 core issues, 2 optional tie-ins/crossovers

PrologueThe Uncanny X-Men #210Setup - Marauders attackCoreThe Uncanny X-Men #211CoreX-Factor #9— Spots!CoreThe Uncanny X-Men #212CoreX-Factor #10— Falling Angel!Tie-InThe New Mutants #46CoreX-Factor #11— Redemption!CoreThe Uncanny X-Men #213Wolverine vs. Sabretooth