Estan diciendo en varios foros de habla inglesa que a eso se le llama ''moneda de reto'' o challenge coin.
Segun la wikipedia:
challenge coin is a small
coin or
medallion, bearing an organization's insignia or
emblem and carried by the organization's members. Traditionally, they might be given to prove membership when challenged and to enhance morale. They are also collected by service members and law enforcement personnel. Historically, challenge coins were presented by unit commanders in recognition of special achievement by a member of the unit. They could also be exchanged in recognition of visits to an organization.
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Osea una masonada, un buen pago para un judas.