The Bog Beast was the disguise of an unnamed man.
Physical appearance[]
It was a gray-skinned creature with reddish-brown roots sticking out of different parts of it's body. It also has brown roots as eyebrows and some sort of mustache and tentacles hanging out it's mouth.
Personality[]
Do to it already being caught it's personality was never shown.
History[]
Scooby-Doo, Where Are You? (DC Comics)[]
Bog Beast unmasked.
The unnamed man dressed up as the Beast to scare people away so he could claim the land at the bog. But his plan was foiled by Mystery Inc. and he was arrested.
The gang later headed to a car wash to get the Mystery Machine cleaned up do to the fact that the Bog Beast covered it in green slime.