Waterwraith

The Waterwraith was a boss-enemy in the second Pikmin game. It resembles a ghostly, human-like creature made of water, therefore earning its name. Based on the in-game notes, its true form exists in another dimension. When it is first encountered, it comes down on a rock and rolls itself with the rock, making it similar to a steamroller as it crushes the Pikmin. The only way to defeat it is to throw purple Pikmin onto it. The force of the Pikmins' weight will cause its true form to come, which looks exactly the same with the difference of turning purple instead of water-textured. It can be freely attacked in this state. After its health is depleted, its rock will break. It now will run around helplessly, although fast. When it runs around for about 7 seconds, it will get tired and turn purple again. It will be defeated after its health depletes a second time.