The Chicken Monster was the disguise of an unnamed criminal hired by Preston Pressman.
It looked like a giant humanoid rooster.
It was willing to fight hand-to-hand even when outnumbered.
Scooby-Doo! (DC Comics)
The Chicken Monster appeared the week Italian Ice was a guest star with the gang. The singer was useless, but he got all the publicity, just as Pressman planned. The hired criminal provided a safe case for the rapper to star in.