The Well-Dweller lived at the bottom of Castle Revolta.
It's a huge purple sea monster with three green eyes and sharp teeth.
The Well Dweller is shown to be dangerous, but he likes to play ball.
Scooby-Doo and the Ghoul School
The Grim Creeper trapped Scooby-Doo, Shaggy Rogers, Scrappy-Doo, and Matches in a huge well of water. The giant Well-Dweller appeared. Matches tried to breathe fire on it, but the water washed his flames out. Scrappy had a better idea: play ball.
Scrappy, Matches, and Scooby hit the ball and the Dweller tried to hit it back. The ball went higher and the monster went after the ball. It was the chance for Scooby and the gang to get out of the well by climbing up its back. Scrappy then let the Dweller keep the ball.
- Scooby-Doo and the Ghoul School (no lines)
- While they were on the Well-Dweller, Shaggy made a joke that it was a "Dwellevator".
- It is unknown what happened to the Well-Dweller after Revolta's castle exploded.