Ultimate X4 001 (of 2) (2006)

Ultimate X4 is a Marvel Comics miniseries, set in the Ultimate Marvel universe outside the mainstream continuity. It features a crossover between the Ultimate X-Men and the Ultimate Fantastic Four. This miniseries is the first canonical team-up of the X-Men and the Fantastic Four in the Ultimate Marvel universe. The arc consists of two parts, UX4 #1 (December 2005) and UX4 #2 (January 2006).