Sludge Goolix

The Sludge Goolix is a species of goolix made of an indescribable substance.

=In fanon games=

In Pikmin 3: Return to the Pikmin Planet
The Sludge Goolix is a boss in Pikmin 3: Return to the Pikmin Planet. It is found only on the sublevel of the Stone Labyrinth in the Desert of Wrath. This boss is not very difficult, but the fight against it can be very long. It looks like a giant black Goolix. The nucleus inside the enemy will glow one of any color to indicate which Pikmin should attack it. Swarm it with that Pikmin color and that color only, as any other color will begin to drown, even if they are Blue Pikmin. This will not do much damage, but it's the only way to attack. After a couple of seconds, it will change colors and the Pikmin inside of it at the time will fly out. It is possible to defeat with only one color; just wait until it changes to the color of available Pikmin again.