Phony Phantom

Asa Shanks A.K.A The Phony Phantom is the hidden true main antagonist of the Scooby-Doo, Where Are You? episode Haunted House Hang-up.

Case History
Fred, Daphne, Velma, Scooby, and Shaggy cruise down a wooded back-road towards a rock festival when they pull up to a farmer on the road who says his name is Asa Shanks. He informs them there is a fork in the road and that they should take the long way, because the short way leads past the mansion, haunted by a Headless specter. After Scooby and the gang search the mansion, they learn that the Headless Specter is actually a man named Penord StillWall who is trying to find his family treasure. Fred and Shaggy go up into the attic to see a man wearing a sheet, chopping the walls of the attic with an axe. Fred and Shaggy chase him outside and the sheeted-figure crashes into a column, making it collapse. The sheeted figure is revealed as Asa Shanks, Penrod's neighbor, who was also looking for the treasure.

Trivia

 * Asa's disguise is the weakest in the first series, if not the entire Scooby-Doo franchise. Inspite of that, Fred and Shaggy are still frightened by him. This could be due to the fact he was holding an axe, although he wasn't holding it when he chased them.