History
Peter’s powers activated when defending himself from his abusive father (who was a widow) During a beating he exploded, killing his father and destroying their house, but thankfully sparing his three younger siblings.
Northstar tried to take Peter to the Xavier Institute but despite his best efforts Peter’s powers keep activating en route, severely injuring him. He refused to go to the hospital fearing that he would take the hospital out with him and died shortly after.
Power
Peter’s mutant power is to explode, but he has little control over it and is not immune to the effects himself.