Mr. Meister is a middle-aged Caucasian male with brown hair and round-shape glasses. When he's not wearing a hazard suit, he wears a lab coat with a tie.
What's New, Scooby-Doo?
He pulled Shaggy and Scooby away from a river of Scooby Snack batter, demanding that they keep their tongues out of the mix. He explained to them that months ago, an employee also wanted a taste, before he fell in and mutated into a monster. He goes on warning the duo that the monster still haunts the factory, advising them in a rude manner that they should leave at once.
While looking for Shaggy and Scooby, Fred wanders into his lab asking if he's seen them. He ignores the subject asking him back if he's after the recipe. Fred denies, but expresses his interest in finding out. This causes Meister to lash out at him believing him and the rest of the gang to be spies, slamming the door on him afterwards.
When the case was solved, he gave Shaggy and Scooby a lifetime supply of Scooby Snacks as a reward, only for them to finish all of them in seconds. However, he gave them a ride on the tour tram, leading them to even more Scooby Snacks.