In Shroom City, Bowser challenges the player to this minigame at Bowser Mansion after the player successfully convicts him. If the player wins the minigame, they receive the game and the GaddgetLip Sync.
The player has to get rid of the Koopa Kids trying to steal all three of their Mushrooms by using a hammer to swing them out of the lane. Some Koopa Kids use tricks to try to get the Mushrooms, such as switching lanes and faking moves toward the other lane. Green Koopa Kids simply walk toward them, blue Koopa Kids take more than one hit to defeat, and red Koopa Kids sometimes try to charge for the Mushrooms. Occasionally, smacking a Koopa Kid out of the area causes an exclamation mark to appear over their heads; the next Koopa Kid the player swings at will roll backward out of the lane, knocking out any Koopa Kids in the same lane. If a Koopa Kid successfully steals one of the Mushrooms, the others begin to move between the lanes. If the player swings all the Koopa Kids out of the lane, the player wins.
