The Scorpio Comet was a comet that was passing near Earth. It was initially a harmless scientific curiosity.
Magneto managed to steal the Mutant Power Circuit while Pyro got the coordinates. On Asteroid M Magneto successfully installed the circuit and using his amplified powers diverted the Scorpio Comet towards Earth.
The X-Men flew to the asteroid aboard the Blackbird. They boarded the asteroid and attacked the Brotherhood of Mutant Terrorists. One by one the X-Men were distracted by the Brotherhood until it was just Nightcrawler.
Nightcrawler found Magneto who only taunted him. He tried to destroy Nightcrawler but Kitty Pryde phased up through the floor to stop him. Magneto was further distracted when a dragon bit his ankle. Magneto accidentally broke the circuit, which meant that nothing could change Scorpio's course.
However, Professor X told Nightcrawler to complete the circuit while Kitty pushed Magneto back onto the platform. The resulting energies pushed away the Scorpio Comet, but sent it towards Asteroid M.
Unfortunately, Nightcrawler must have continued completing the circuit or else the comet would head back towards Earth. Magneto left with the Brotherhood back to Earth. Nightcrawler told Kitty to leave, as does Xavier since he had a plan. She grabbed the dragon and headed back towards the Blackbird.
Xavier kept the Blackbird on a viewscreen that Nightcrawler could see. Xavier told him that he must teleport aboard at the very last second. The plan worked and the comet hit the asteroid destroying both.
Scorpio was named after the astrological symbol.
- Comet at Wikipedia