Complex sentence: Accompanying them on their adventures was a creature known as the Dorse (played by Larry Larsen) which was a half-dog, half-horse hybrid with the body of a large shaggy dog and the head of a small horse.
Split into simpler sentences: Accompanying them on their adventures was a creature known as the Dorse. It had the body of a large, shaggy dog, and the head of a small horse.