*X-Men (Vol 1) #104
Visiting the Mutant Research Center on Muir Island, Wolverine, Banshee, Storm, Nightcrawler and Colossus didn't realize that the X-Men's greatest foe, magneto, had escaped his special prison cell in the complex. The mutant master of magnetism unleashed his near-limitless power, and was about to destroy them when Cyclops arrived. The team's leader was the only X-Man who had experience battling Magneto, and was able to fight him to a standstill. Before Magneto could launch a new attack, the X-Men left for the U.S. to save their mentor, Professor X, from an assassination attempt. *Source: Back of Card