Female Sheargrub

These creatures are totally harmless to your pikmin (unlike the males) but can be annoying.

How to kill
In Pikmin they pose no threat but if you are in the forest of hope it will cause problems. If the carcasses are in the way of the pikmin running away they can indirectly kill them. Just throw 3 or more since if one pikmin is there they can burrow underground and regenerate.