Monster mask magic

Monster disguises are extremely powerful in the Scooby-Doo universe. They are far more likely to be taken at face value as real monsters than in our world (which may be a villainous counterpart to the disguise tricks of the heroes). In addition, they seem to have powerful properties of their own that may be the result of toon physics.

Magical costume properties

 * Monster masks allow people to have huge mouths, sometimes with weird properties like smaller faces inside, like the Ghost shown here.
 * Masks can make people's eyes glow or appear a different color, without obscuring their sight.
 * Ghost costumes can make people semi-transparent, as in Guess Who's Knott Coming to Dinner.
 * Costumes seem to give their wearers extraordinary strength and fighting skill. An out-of-shape bank manager can take out a bank guard if he's in a Creeper outfit.
 * One mask can be worn over another, with no problems of volume. They can be worn over large hairdos, large noses, glasses, and hats. This is like the "bigger on the inside" power of Scooby-Doo's doghouse.
 * Costumes can hide the form of a large person and make them appear smaller. Examples include the skeletal arms of the Ghost of Buster McMuttMauler and the spindly arms and legs of Stinkweed. If the contrast would too extreme, the villain may be captured in a way that leaves only their head showing at the time of the unmasking.
 * A more extreme example is the costume that gave J.C. Chasez the form and four-legged running skills of Scooby-Doo, while his extras impersonating the gang gained super-strength.
 * A mask of a real person allows near-perfect impersonation, fooling even people who know them well, in broad daylight.
 * No matter how it appeared when worn or what properties it had, the mask become soft and rubbery on removal, and the eye and mouth holes appear as empty holes.