Giant-Size Astonishing X-Men #1 (Marvel, 2008) One-shot.

Colossus is in the core of the Breakworld's power source, where he must choose if he will let the planet live or die. He makes his choice, and fights to defend it, unaware that Kitty is riding a doomsday weapon back toward Earth. While Colossus single-handedly saves the Breakworld, the other X-Men call upon the aid of the Fantastic Four, the Avengers, and every other hero they can locate to try and save Earth, but in the end, it is Kitty Pryde alone who saves the planet, at great personal cost to herself.

Bagged & Boarded.