Stampede is a challenge minigame that only appears in Mario Party 8.
Gameplay
The character will have a lot of papers in front of him or her. The player must then push the Wii Remote down making the character stamp a paper with his or her letter/picture etc. (for example Mario has a red M, Princess Peach has a crown, Yoshi has a green egg etc.) When the player reaches 20 stamped papers he or she wins.
However there are times when the player will see a paper already been stamped by Bowser. The player needs to press the A or B button, to move the paper out of the way and he/she gets to keep stamping until time is up. If the player stamps the paper with Bowser, the player loses 2 points from your current score. Since there's only 20 seconds, it's slightly hard to stamp all 20 papers.