Complex sentence: Starting in the season three episode "I Am Become Death", the character Mohinder Suresh develops abilities of super strength which at first seem harmless; later on however, he develops an adverse reaction turning him into a monster.
Split into simpler sentences: Starting in the season three episode "I Am Become Death", the character Mohinder Suresh develops abilities of super strength which at first seems to be okay. Later however he develops an adverse reaction turning him into a monster.