Monster disguises are mainly used by the villains of various foes of Mystery Inc. Most of the time these are used to scare intruders away from some sort of criminal endeavor such as a smuggling or counterfeiting. Other times they are used as a disguise while the villain tries to steal an object such as a rare jewel or valuable formula. Most people are fooled by the costume due to monster mask magic, which makes the disguise look very real. A few who have used these disguises have done so for noble reasons such as protecting an archeology site from tomb robbers. Mystery Inc. members Velma, Shaggy, and Scooby-Doo have been involved in such scares.