Complex sentence: The Overlord then betrays and possesses Garmadon's body turning him into a crocodile-like monster which defeats Lloyd, injuring his leg and destroying the Bounty in the process.
Split into simpler sentences: The Overlord then betrays and possesses Garmadon's body turning him into a crocodile-like monster. The creature defeats Lloyd, injuring his leg and destroying the Bounty in the process.