Servantes are props

Theatrical property

A theatrical property, commonly referred to as a prop, is an object used on stage by actors to further the plot or story line of a theatrical production. Smaller props are referred to as "hand props". Larger props may also be set decoration, such as a chair or table. The difference between a set...

 used by magicians

Magic (illusion)

Magic is a performing art that entertains audiences by staging tricks or creating illusions of seemingly impossible or supernatural feats using natural means...

. They've been common objects ever since the very first magicians and many still can't do without. The earliest form is a simple open bag or pouch, often with a ring to keep it open, hanging from the magician's belt. Currently the most used form is a bag or small platform hanging out of sight behind the magician's table. Some magicians prefer to keep it a concealed, secret object, others use it in plain sight to store cards, cups, balls and so on. In the right hands it's still a very powerful tool of deception

Deception

Deception, beguilement, deceit, bluff, mystification, bad faith, and subterfuge are acts to propagate beliefs that are not true, or not the whole truth . Deception can involve dissimulation, propaganda, and sleight of hand. It can employ distraction, camouflage or concealment...

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