Havok
Alex Summers was separated from his older brother Cyclops during a traumatic plane crash that killed their parents. Alex grew up with a foster family, unaware of his mutant powers until his college years, when he was kidnapped by the Living Monolith.
The Monolith intended to use Alex as a fuel source to grow all-powerful and conquer and stuff. However, the X-Men came to the rescue, and Alex was reunited with his brother. Now aware of his mutant ability to fire plasma blasts, Havok became a proud member of the X-Men.