Complex sentence: Harold tells Scott he is responsible for vice principal Rusty Thorne breathing down his neck, due to a scare he'd given him when he was in high school, and advises him to be himself and not the wolf.
Split into simpler sentences: Harold tells Scott he is responsible for Vice Principal Rusty Thorne breathing down his neck, due to a scare he'd given him when he was in high school. He then advises him to be himself and not the wolf.