Roach Smash

From the Super Mario Wiki

Roach Smash is a mini-game in Wario: Master of Disguise. In this mini-game, the player must smash (using the stylus) the coackroaches that walk by. There are a lot of coackroaches, and smashing them all is not necessary-there is a certain number of coackroaches that must be smashed (they depend on the level of difficulty the player is playing the mini-game).