Segmented Crawbster

The Segmented Crawbster is a crab-like creature has one large arm and an exceedingly smaller left arm. It also has a rather thick shell protecting it. This creature rolls after the active leader, occasionally crushing Pikmin with its hard shell. If it crashes into a wall, it can cause boulders to fall. It will then struggle to get back up in an upright position, and while doing so will expose its weak spot: its flashing underbelly. Eventually, it will then get back up and swing its large arm around back and forth two or so times and continue its assault. Once defeated, the Segmented Crawbster will groan and squeal as it is underbelly explodes violently, spewing goo particles all over the immediate vicinity.

Olimar's notes

 * "This gigantic beast is wrapped in a hard shell. In an atypical evolution, the right front leg of this creature is hypertrophic, taking on the function of an arm, rather than a leg. Its asymmetric physical development is unique in the natural world. One unlucky explorer's incorrect conclusion that this creature adheres to a pattern of peaceful, quiet behavior led to an unfortunate incident. In fact, this beast exhibits intensely hostile, aggressive tendencies, aiming at prey and ramming them at full speed."

Louie's notes

 * "Dessert meats are all the rage on Hocotate. When the planet's finest chefs hear about the kind of sorbets, pies, and parfaits you can make with the claw meat on this sweet beast, they'll clamor for every morsel we bring home!"

Pikmin: Redemption
These are more common and sometimes when your on a sublevel above where you fight one you can hear this creature pounding the floor and walls.

Pikmin: Sinister Incinerator
Although Segmented Crawbsters can be fought as recurring minibosses in a few caves like a variety of other foes, the one that serves as the boss of the Dark Wetland Cave in the Ancient Wetland and is intentionally much harder to defeat, as it holds one of the Dark Spores. This Crawbster, in particular, is called the Reconstructed Crawbster.

Pikmin: The After Years
Although the Segmented Crawbster appears twice in the game, once in the Cave of Screams and another time in the Rememberance Ravine, it has a new member in its family called the Clambering Crawbster that appears on the final sublevel of Crawbster Cave.

Pikmin Eco
The Segmented Crawbster is the boss from Shimmering Seaside's Bone Cove, and the only Pikmin 2-exclusive boss to make a return in Pikmin Eco. While it physically is the same as its previous appearance, its behavior differs greatly. The area where you fight it also differs the strategy: fighting it inside a hollowed-out coral shell, where water can splash inside the arena during the battle to flood it, and then drain sometime later.

Strategy
The Segmented Crawbster has two main "mode" in the battle depending on the water level:
 * When there's no water, it crawls slowly on the ground. If the player gets too close, it will swing its larger claw to knock you and your Pikmin back. On occasion it will slam the ground with its huge claw, crushing any Pikmin underneath it. This will cause rocks to fall from the roof.
 * When the arena becomes flooded, it will float along the surface of the water and swim around. It will also try to swing its huge claw around, but since it's swimming the swings are much more ranged.

When it is swimming, you need to send your Winged Pikmin to try and push the Segmented Crawbster around so it's upside down. When the arena drains, it will land on its back and get stuck, which exposes its vulnerable underbelly to attack. Eventually it will swing itself back onto its stomach, so you can't kill it in one shot.

Pikmin Galaxy Adventure
It doesn't appear simply as a boss. It appears multiple times, but it is much easier than in Pikmin 2. Various Subspecies exist such as the Jungle Crawbster.