Ravenous Whiskerpillar

The Ravenous Whiskerpillar is an enemy in Pikmin 2. These enemies are not harmful to the Pikmin, but are dangerous to the Burgeoning Spiderwort plants. They will eat the berries on the plants, which are necessary to make sprays. They can be found in the Awakening Wood, the Perplexing Pool and the Wistful Wild; each time, they are near two or more Burgeoning Spiderwort plants. When confronted on a Burgeoning Spiderwort, they will drop off the plant and burrow into the ground, giving the player a chance to attack it. Strangely enough, when killed, they don't seem to be dead; carrying them will make them squirm and emit more of their hissing, and a soul does not appear. Just before they are pulled into the Onion, they struggle and hiss even more rapidly. The in-game Piklopedia states that they are a larval form of another creature, but it says that mature specimens have not been found yet. Interestingly, even though it is the only enemy that does not appear in any underground areas, it has a treasure value of 1 Poko according to the Piklopedia.

Pikmin
If it's on a Burgeoning Spiderwort, send a couple of Pikmin up there to bring it down, then swarm it with the rest when it falls. Otherwise, just swarm it.

Leaders
If it's on a Burgeoning Spiderwort, then wait for it to eat all the berries and kill it when it hops off of the plant. If on the ground, just punch it until it's dead. If the Rocket Fist upgrade has been unlocked, the third punch can hit the Whiskerpillar only when it's on the very bottom part of the berries.

Trivia

 * An enemy similar to the Ravenous Whiskerpillar was meant to appear in Pikmin 3, according to some unused files.
 * Louie's recipe implies that he killed the specimen itself, as the Whiskerpillar does not die when defeated by the Pikmin.