The gang goes to the barbecue, and all but Shaggy and Scooby-Doo go off to see the paleontological dig of Professor Svankmajor. Shaggy and Scooby are too full to walk right away. When they set out, a gila monster steals a biscuit from them, causing Scooby to go after it. He meets the Phantosaur and runs away. Later, Shaggy and Scooby are chased by the Phantosaur and narrowly escape.
