Complex sentence: Ultimately, however, Shaggy chooses to make a deal with Dracula, and states that he'll only race under the condition that if he wins, Dracula must return him back to his human state, and allow him and his friends to leave.
Split into simpler sentences: Ultimately, however, Shaggy chooses to make a deal with Dracula, and states that he'll race. On condition that if he wins, Dracula must return him back to his human state, and allow him and his friends to leave.