A cross-over event started in late 1986. Involving mainly the Uncanny X-Men and X-Factor, the cross-over also made it’s way into an issue of Daredevil and Thor - as well as Power Pack and New Mutants. The success of Mutant Massacre led Marvel Comics to start holding cross-overs annually.
“The Morning After” -- 22 pages
- written by Chris Claremont; pencils by John Romita, Jr.; inks by Dan Green
“Massacre” -- 22 pages
- written by Chris Claremont; pencils by Bret Blevins and John Romita, Jr.; inks by Al Williamson
“The Last Run” -- 22 pages
- written by Chris Claremont; pencils by Rick Leonardi; inks by Dan Green
“Psylocke” -- 22 pages
- written by Chris Claremont; pencils by Alan Davis; inks by Paul Neary