Acidic Dweevil

The Acidic Dweevil is a subspecies of Dweevil that uses acid to attack. Green Pikmin are invaluable when faced with an Acidic Dweevil, as they are immune to the acid's effects.

=In other games=

In Pikmin: Sinister Incinerator and Pikmin: The After Years
The Sulfuric Dweevil is a green dweevil that has red eyes and defends itself with acid it secretes from its body. They behave like most other dweevils, running away from leaders and Pikmin as well as picking up objects and attempting to mimic them. Green Pikmin are extremely useful when fighting the Sulfuric Dweevil.

In Pikmin: Shadows of the Future
The Chlorine Dweevil is a small green dweevil with purple eyes and uses acidic gas to defend itself from predators. The clouds of acid mist it releases are quite effective in killing Pikmin other than Green Pikmin. The Chlorine Dweevil is incredibly similar to the Sulfuric Dweevil, but attacks differently than it. However, like most dweevils, the Chlorine Dweevil doesn't actively seek Pikmin out, only fleeing from them and leaders if they get too close, and attacking when the creature itself is attacked.