The Goolix (ミズモチ "Mizumochi") is a water-based boss in the first Pikmin game; on approaching its location, it emerges from the ground. It resembles a blue amoeba with two nuclei (a smaller blue one and a larger yellow one). It stretches around to engulf Pikmin who happen to be in its path and drowns them out with its aquatic properties. The only Pikmin invulnerable to it are Blue Pikmin, due to it being composed mostly of water. Its weak point is the smaller nucleus. If it is attacked, it will smack the nuclei together, knocking off all Pikmin on it, though it may cause more damage. Throwing a Pikmin on the yellow nuclei will make all the Pikmin bounce off, but deal a little more damage than a normal attack. When it is defeated, its membrane breaks and its watery insides spray out in all directions, leaving no trace it was ever there, besides dropping 4 random colored 5 pellets. It is only found in The Impact Site on odd-numbered days starting from day 9 (even-numbered days starting from day 8 will have the Mamuta instead).
Unless you attack the bigger, yellow nucleus, it will take a long time to defeat.
"Within the transparent gel that envelops this organism are two nuclei that appear to make up its actual torso - and most likely its entire nerve center. The nuclei look like they're hard, but I believe that there must be some way to crack them."
"A watery gelatinous membrane protects this creature's nervous system."
"Floating within the Greater Water Slime's transparent body are its duel nuclei. The Greater Water Slime's system is contained within its main nucleus, which displays a marbleized sheen. The Greater Water Slime's secondary nucleus is beige and serves as a defense system to weaken prey and nutrients that have been absorbed through the organism's amorphous membrane. Prior to absorption, most prey will succumb to the watery membrane, which coats the Greater Water Slime's body."
If the Goolix is near the right of the tree-stump arena and the yellow, brain-like nucleus is hit by a Blue Pikmin, that Pikmin, or the other Blues that are attacking the smaller, blue nucleus may be knocked into the out-of-bounds, forest like terrain. Many things can happen when this occurs, either the Pikmin will slide around (throwing Pikmin onto this ledge reveals that it's slippery, as the Pikmin will slide off) and then fall off the ledge and into the area with the Pearly Clamclamps or where the Main Engine was, or they slide too far for Olimar to call back (Some will even continue sliding until they are off-screen and then will die). These Pikmin will be left behind unless you do not save and reset the day.
- In the Goolix's scientific name, Binuclei siphonophorus, the "bi" part means two or double. The "nuclei" part means nucleus, and the "siphonophorus" part means "Hydrozoa", a group of invertebrates with a gelatinous appearance. It also means "blob". So, it means Double Nucleus Hydrozoa.
- When not in motion, the Goolix has almost exactly the same proportions as a nectar or spray drop.
- The Goolix is one of the three enemies in the series so far who are almost completely liquid-based. (with the other being the Waterwraith in Pikmin 2, and the Plasm Wraith in Pikmin 3).
- In the Creature Montage, The Goolix appears in The Forest Navel.
- This enemy was the only way to see the "water suffocation" animation in the first game.
- The Goolix is one of the five enemies in Pikmin that does not reappear in subsequent games.
- Its Japanese name could mean "Water Cake".