Originally Posted by SlowRolla

Did any of you guys watch the scene at the end of the credits?

Originally Posted by MrFatbooty

In the scene where Professor X is giving the lecture, he shows a video where this doctor he knows, Moira MacTaggart, is watching over some dude who has a fully functioning body and nervous system, but no consciousness. He asks the class what they think would happen if a consciousness were to be transferred into his body. Then in the scene at Jean Grey's house, Phoenix is trying to evaporate Xavier or whatever that trick she does is, and he's resisting her which is why he holds on so long. There's that instant where everything slows down, Xavier flashes a smile (you can barely see it) and then poof he disappears. In the scene at the end after the credits when you see the dude from the video, he wakes up and says "hello Moira" with Professor X's voice.

So the theory goes, Xavier knew going into it that Jean/Phoenix is the most powerful mutant on the planet and she could probably eff him up pretty good, and he wouldn't go into a situation like that without some sort of escape plan. Plus he already knew about the dude Moira was watching over, so when he realized he couldn't stand up to Phoenix's powers, he hopped his consciousness over to that other dude's body. Once Xavier's consciousness left his own body, he couldn't resist Jean's powers any more and he just goes poof.