Soon after, Xavier left the school temporarily to aid Moira in some research on Muir Island. While he's away, the school is attacked by Alpha Flight whose mutant powers are enhanced by a drug called Banshee. Furthermore, it is revealed that Colossus has been using Banshee during his entire time at the Xavier's School, in order to use his power without pain. Due to the sudden and apparently rampant use of the drug, Xavier and Jean begin screening all the students for traces of Banshee. However, it is later revealed the Banshee drug was created by Xavier himself, during his time in the Savage Land, and that it was created from Wolverine's blood. When Xavier tested Banshee, he was given powers that mimicked Wolverine's, including claws, enhanced senses, and a healing factor. Xavier and Magneto, however, deemed the drug too dangerous and stopped production of it. When Wolverine discovered that he was the source of the drug and that Xavier was responsible for its initial creation, Wolverine attacked Muir Island. Xavier admits to creating the drug but denies that he is responsible for its continued creation and use. It is revealed then that Moira got hold of Xavier's research and began creating and selling the drug in order to finance Muir Island. Moira, who had used the drug to give herself a sonic scream, begins to do battle with Wolverine, and Xavier evacuates the children moments before the research facility explodes.