"A challenge coin is a small coin or medallion (usually military), bearing an organization’s insignia or emblem and carried by the organization’s members. Traditionally, they are given to prove membership when challenged and to enhance morale. In addition, they are also collected by service members. In practice, challenge coins are normally presented by unit commanders in recognition of special achievement by a member of the unit. They are also exchanged in recognition of visits to an organization."
They are also used in a drinking game the one with the highest ranking coin is bought drinks by the lower ranking coins.
I collect tokens, and they are a subset of them.
Zombie themed shooting events are popular in my area, at the local ranges
