"The Hellfire Gambit"
Kitty and Ororo (in Emma's body) infiltrate the mansion where the Hellfire Club are holding the X-Men captive, but when Wolverine is left for dead, he teams up with Kitty to free the X-Men. Emma in Ororo's body lets loose an uncontrollable storm, but the two switch back and the real Ororo calms the storm and ends the fight.