Mr. Buckston was the president of the Coolsville Last National Bank. He dressed up as the Sludge Monster from the Earth's Core to scare Scooby-Doo away from his doghouse so he could use it as a hideout for all the gold he stole from his bank and frame Mr. Williams, the bank's janitor.
Mr. Buckston is a middle-aged Caucasian male, with short brown hair. He wore a blue suit with gray pants. His clothes were buttoned improperly, which Velma Dinkley noted as being suspicious.
He appeared to be concerned about his bank being robbed, but this was to cover his tracks and accuse one of his employees of embezzlement.
A Pup Named Scooby-Doo
He made a phone call to the police, seeing to it that Mr. Williams was found and arrested for the bank robbery.
When the Sludge Monster was unmasked and discovered to really be Mr. Buckston, Velma revealed that when he arrived at the scene after the phone call to the police, his clothes were sloppy, which showed that he must have changed clothes in a big hurry to arrive at the scene and cover his trail in framing Mr. Williams.