The Adventures of the X-Men #12

Synopsis

When the Dweller in Darkness and D'Spayre threaten the universe by corrupting the M'Kraan Crystal, Lilandra asks Jean Grey to once again combine with the power of the Phoenix Force to combat them. When the crystal cannot be repaired, Jean and the X-Men touch the minds of everyone in the universe with peace as the jewel explodes and destroys the universe. The alien Galen is the only survivor and becomes Galactus. Millennia pass as the new universe spawns life on Earth and, eventually, the original X-Men are reformed.