Shy Guy Smash!
From the Super Mario Wiki
There are six Warp Pipes in which Shy Guys will pop in and out of; the player must touch the Shy Guys with the stylus. However, touching Bob-ombs will detract 5 points from the score. 25 Shy Guys is the amount needed to win, but each time the player wins, the goal is automatically set to the player's new record.
In the first-floor minigame, the pipes are all in a straight line, and no Bob-ombs appear. The second-floor minigame introduces Bob-ombs, and there are three pipes on the bottom and three on the top.