Toon physics are rules of how the universe works in cartoons. While most of the characters in the Scooby-Doo universe are relatively realistic, others have a higher degree of "tooniness" which gives them what amounts to super-powers.
Scooby-Doo possesses this ability to a high degree, and so do other talking canines related to him. Shaggy Rogers has a slightly lesser power. The rest of the gang has only mild tooniness (they had more when they were children).
Rules of toon physics
- Gravity has no affect on a character unless they look down and become aware they should fall.
- Fear cancels gravity. A scared character can leap to arbitrary heights.
- Rebounds increase momentum.
- A running character can crash through any wall, leaving a silhouette conforming to their outline.
- Characters can contort and fit into any container.
- Inflating someone with air can make them balloon out and become lighter than air.
- Releasing the pressure on something filled with air converts it into a jet-propelled rocket. The flight will inevitably land on the villain or do something funny.
- Characters can produce arbitrary objects from thin air, or "hammerspace."
- Creating a situation with disguises will fool the smartest villain, at least for a short time.
- The Scooby-Dooby doors effect allows character being chased from one room to another, or who are being looked for in a set of containers, to automatically appear in different rooms or containers without regard to how they got there.
Shaggy sometimes demonstrates knowledge of Scooby's powers and treats him a bit like a genii. For example, when they were being chased by Vikings in a hand-car and needed a way to escape, Shaggy asked Scooby to "think of something" that would help. Scooby produced a flying bicycle from hammerspace that they used to fly away.