Chickenstein was a 7-foot-tall humanoid chicken creature with white feathers, red eyes, sharp teeth, and an open black vest. His hair, flat head, and stitches on his body bring to mind Frankenstein's monster, hence the name.
He would often cluck like a chicken, but in a low-pitched, angry-sounding voice. When speaking, he occasionally substituted the "ex-" at the beginning of words with "egg" to go with the chicken theme.
Powers and abilities
He was very strong, being capable of busting right through walls.
A Pup Named Scooby-Doo
The gang first encountered Chickenstein in the office of Sam Schlock, a reporter for the National Exaggerator. They fled and barricaded the door, seemingly trapping him inside. They informed Freddie Jones' uncle Eddie, who had just bought the Exaggerator, that they had captured Chickenstein. Eddie mentioned that Chickenstein had been scaring all of his employees away. Chickenstein busted out of the room, leaving a monster-shaped hole in the wall. He left dirt near the hole, which came from the Coolsville Cemetery.
The gang investigated the cemetery and split up to search for clues. Shaggy Rogers and Scooby-Doo found the nest of Chickenstein inside a mausoleum. They were scared away when Chickenstein came through the wall and chased them off. They rejoined the rest of the gang, who were paying a visit to Granny Sweetwater. Granny claimed that she was responsible for Chickenstein, and proceeded to demonstrate how she caused him to appear. Suddenly, the lights went off, and when they came back on, Granny was gone, and Chickenstein had appeared. The gang lost him by hiding in the bushes (and a mailbox) outside the house.
When they returned to the cemetery, they saw Chickenstein enter a mausoleum - the same one where his nest was. They followed him in, where Scooby found pillows and glue. Just then, Chickenstein popped out of the nest, and a chase ensued. The gang eventually lost him in Granny Sweetwater's basement, where they found loads of new merchandise. Velma Dinkley solved the mystery and came up with a plan.
The gang set a trap for Chickenstein, which ended up backfiring. Chickenstein chased Shaggy, Scooby, and Freddie until they slipped on some oil and fell into a pile of magazines where the monster cornered them. Scooby hit a nearby lever, which caused a crane arm to grab Chickenstein and drop him into a hay baler, baling him into a square heap of feathers.
Eddie was excited to meet Chickenstein, but the monster wasn't real, much to his and Freddie's disappointment. Velma revealed Chickenstein's true identity to be Casmer Codwaller, a man the gang had seemingly never met. However, Velma added a gray wig, making him look like Granny Sweetwater, who was really Casmer all along. He pretended to be Granny as a cover for him selling stolen merchandise, which he had in his basement. When Scoop Byline started snooping around his house, he tried to get rid of him by disguising himself as Chickenstein and scaring the Exaggerator out of business so Scoop would lose his job.
Scooby-Doo 2: Monsters Unleashed
Velma noted him while walking through the Mystery Inc. exhibit at the Coolsonian Criminology Museum as one of the more ridiculous monsters that the gang has encountered. Oddly, the costume didn't resemble the original monster very much. According to the cast commentary, there was suppose to be a reference to Chickenstein in the first film as well but this did not make the final cut.