Challenge coin

A challenge coin is like a special shiny medal that people give to each other as a reward for doing something really cool or important. It's usually round, and has a picture or a symbol on it that stands for a group or organization. People who have the coin feel really proud of it and might carry it around with them everywhere they go. Sometimes, if someone with a challenge coin pulls it out, they might challenge someone else to show their own challenge coin. If the other person doesn't have one, they might have to do something funny or silly to make up for it. It's kind of like a game, but with really cool shiny medals as the prize.