Sheargrub
Sheargrub
Himeagea mandibulosa
Sheargrubs are enemies in both Pikmin games. They burrow underground, and when you approach, they dig out of the ground's crust. The Sheargrub species come in two colors, pink and purple. Pink Sheargrubs are female, and they don't do much anything when they come out of the ground. It is stated that they feed on dead Pikmin remains, but they can't harm your Pikmin. Purple Sheargrubs are male, and they have larger mandibles, allowing them to eat your Pikmin whole. This creature isn't dangerous though, you should easily be able to kill this creature and save your Pikmin by swarming it. However, if in Pikmin 1, they are in their mouths, the only way to kill it is to throw a Pikmin on top of it to save the Pikmin, otherwise it will die if the pikmin isn't saved and it has no remaining health, similar to the way in beating Dwarf Bulborbs. This supplies the fact they were harder to kill in the old game without losing Pikmin.
Sheargrubs also like to eat wood (maybe), and will try to deconstruct the bridges you have built. You may want to stop them every now and then and keep them frow destroying the bridge. Even if they completely ruin it, it can still be rebuilt. Every 2 or 3 days you kill those opposing Sheargrubs, they'll come back, so keep that in mind.
These creatures are also related to the Shearwig.
How to Kill
Pikmin
Female
Swarm and forget.
Male
Swarm it. It may eat a Pikmin, but you'll save it if you kill it before it finishes off the Pikmin.
Captains
Female
Simply attack it until it dies.
Male
Attack from the sides until it dies.