From the Super Mario Wiki, the Mario encyclopedia
The player must slap Wario's face to wake him up. Even after Wario wakes up, the player can continue slapping him. Waking Wario up turns the night sky to morning. In a 16-second/32-beat version of this microgame in Kelorometer, Wario does not wake up regardless of how many times he is slapped. Also, the command is changed from "Wake up!" to "Hit!"