Complex sentence: Blanka was once known as Jimmy, and as a little boy he was in a plane crash that landed in the Amazon rainforest where he was exposed to electric eels, mutating his appearance and giving him electric powers.
Split into simpler sentences: Blanka was once known as Jimmy, before he was in a plane crash as a little boy. Blanka's plane landed in the Amazon rainforest and he was exposed to electric eels, mutating his appearance and giving him electric powers.