Ice fan

An Ice Fan is an object in Dr. Mario World. Introduced in World 7, the fan will turn on if objects next to it are eliminated. If the player does it again, the fan will hide a random virus in ice. It can also effect some items (shells, exploders, skill chargers, pop cannons, or electric exploders), and when an object is half frozen and the fan hides it again, it will be fully frozen. Dr. Morton's skill can change them into empty blocks, causing the fan to be deactivated until the player returns to that stage.