Ultimate X4

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).

Story

The X-Men receive a seemingly alien distress signal and fly away with the Blackbird to track it down. Only Wolverine, Shadowcat and Iceman remain at the X-Mansion. In the meanwhile, Rhona Burchill, the Mad Thinker, raids the understaffed X-Mansion and steals Cerebro, and manages to frame the Fantastic Four for this crime.

Rhona reveals that she was contracted by Advanced Idea Mechanics (AIM) to steal Cerebro and turn it over to them. After being paid for her work, Rhona betrays and kills the AIM operatives sent to retrieve Cerebro, since her true intention was to use Cerebro's technology to increase her intellect even further.