A 1995-1996 Marvel crossover spanning over 40 issues across X-Men: Alpha, X-Men: Omega, Astonishing X-Men, and Amazing X-Men. Created by Scott Lobdell, Mark Waid, and Fabian Nicieza with art by Joe Madureira, Andy Kubert, and Chris Bachalo.
Set in an alternate reality where Charles Xavier is killed before founding the X-Men, leading to a dystopian world ruled by Apocalypse. Magneto leads the X-Men in this reality. The event introduced new characters and remains a fan-favorite for its alternate setting.