Broly

Broly was a saiyan born with a power level of over 10,000. This level continued to grow until his death, where it ended at 1,000,000,000. His shattered psyche made him violent and uncontrollable. He crashed on Earth around 1733 and destroyed the town of Ottessen in a single night, leaving nothing but a crater of destruction behind. The Adventure Group confronted him and were killed by his awesome power, before being saved by the Time Lord, Amell. Once ressurrected, they finished Broly off for good.