The mollusking family consists of two known species. Attached to the backs of these large, slug-like mollusks is a frilly appendage resembling a berry or a flower bud which functions as the creatures' gills. Such an outlandish means of respiration may seem far-fetched, but a real-world order of snails and slugs called nudibranchs breathe through colorful frills on their backs. Technically, in Pikmin 2, both enemies are the same, but Toady Bloysters are given special traits to decrease their size, and lack the leader chasing mechanic.
All members of this family are in the Molluschid genus.
The Ranging Bloyster is a large form of the Toady Bloyster, named for its longer tentacle mouthparts and bigger size. This creature is difficult to beat because it tracks the player's active leader. Whatever color the leader's antenna beacon is, the eyes and tail of the Bloyster will change to that color; it also emits a different sound depending on the leader's color.
The best way to beat it is to lead one of the leaders behind the creature and then have the other leader while the Bloyster faces the diversion leader, and start throwing them on its back or tail while the Bloyster can't face the leader. If it turns around, switching to the other leader to refresh the diversion is a good strategy.
Toady Bloysters are slug-like creatures that creep along the ground in search of food, and upon discovering Pikmin, they lash out their adhesive pseudopodia-like tentacles. Any Pikmin hit by the tentacles stick, and are ingested if the Bloyster is not killed before it can finish "chewing". The gill-like organ on its back is its weak point, being the only damageable spot in Pikmin 2, and a source of extra damage in Pikmin 3.
When damaged, they attack by shaking their tail in Pikmin 2, and emitting non-fatal ink in Pikmin 3. Because the only Toady Bloyster in the game holds a treasure (the Aquatic Mine), entering a cave makes it respawn. Thanks to this, it is a very low-risk method of spawning large amounts of Pikmin in a short amount of time.
The family's name is an alteration of the word mollusk. Members of this family use the word "Bloyster" in their name. "Bloyster" is a gibberish alteration of "oyster", the pearl some mollusks can create; it could possibly be a portmanteau of "bloat" and "oyster," given the bloated look of the creature. Their scientific names use Molluschid for the genus name, which is similar to "mollusk".