As in the Mario series when one gains a green mushroom the words "one up" flash on the screen, this is when you tell a story and someone else tries to tell a story better than you.
John: "i once skydived"
Bob: "yeah well i skydived and shot 4 ninjas whilst slaying a dragon and throwing the ring into Mt. Doom."
John: "Green Mushroom me again and you die."
Prices shown in USD.