Beetle was a member of the 'Terrible Three', together with Beast and Beak. As a trio, they were not known for doing a good job, and after they failed to capture young Corky and Tony, who were tresspassing in Hauntquarters, Prime Evil vowed to turn the three of them into the 'Terrible Six'.
Beetle first appeared in the episode The Sleeping Dragon.
The Sleeping Dragon (none-speaking role)
The Fourth Ghostbuster (none-speaking role)