The Monstrous Freak was the disguise of the spirit of El Aguirre.
He was pale looking and had a frightening skull-like face with long black dreadlocks. He was muscular, only wearing a loin cloth.
He acted primitively, snarling and scaring people with its fangs.
Powers and abilities
- Teleportation: As a supernatural entity, he can appear and disappear in a mass of swirling black lines. This takes time, so an agile person like Velma Dinkley can leap through him while he is taking form.
Scooby-Doo! Mystery Incorporated
He used the disguise to keep Mystery Incorporated in the sitting room so they wouldn't destroy the evil entity that was in the crystal sarcophagus, because it would set him and his men free; he wanted to stay there so they could pay for past evil deeds. He was found to be vulnerable to the light coming from the statues of the Hunters of Secrets.