|This needs a stretch.|
Queen Morbidia is one of the demons from the Chest of Demons.
Queen Morbidia is (presumably) a vampire, who appears as a beautiful middle-aged woman. She has black hair with a white streak down the middle, and wears a tight red dress which accentuates her shapely figure. The sleeves of the dress are tattered to resemble the wings of a bat.
She resembles Lilly Munster, the matriarch of the Munster clan in the TV series "The Munsters."
Queen Morbidia is obviously the leader of the assembled monsters. She is bold, arrogant and cruel, but is also a touch oblivious... for instance, she didn't even think to check her bedchamber for the stolen Chest of Demons, even though it was in Befuddle Hall and thus a possible location.
The 13 Ghosts of Scooby-Doo
Queen Morbidia leads all of the convention attendee monsters in pursuit of the gang when they retrieve the chest, and chase lasts all night. When the gang is cornered (outside), the gang sings their "last words" in a projected, overlong song to kill time. The ruse works and the sun arises. The sun turns Queen Morbidia to a pile of ash, which Flim-Flam then scoops up and dumps into the Chest of Demons.
It is unclear if Morbidia was actually destroyed by the sun or not. If she was, dumping the ashes in the Chest was not necessary, as that was the end of her.