Water Beetle

The Water Beetle is an enemy that was first introduced in the game Pikmin:The After Years. Unlike Anode Beetles, they have blue spots and spray water when two of them meet. This attack will drown all but Blue Pikmin.

How to Kill
Throwing a Blue Pikmin on top if it will flip it over and because they are immune to water, they won't drown. A Purple Pikmin will also flip multiple of these beasts over due to the shock-waves they create.

-- Gamefreak75

Yoshord's Notes
This species has very little tolerance for differences in pH. Unrelated, but all essential, proteins have very little overlap in desirable conditions. The creatures also pick up environmental acids or bases very easily. These factors combined tend to lead to unstable organisms. However, since these creatures travel in groups, it is likely that if one member of the group is becoming too acidic, another is becoming too basic or vice-versa. The obvious solution at this point is to mix the body fluids of the two oppositely oriented creatures, and split all acids and bases evenly between the two creatures. The result is two organisms now both near their desired pH. Any salts created by the meeting of acid or base can act as natural seasoning if the right salts are produced.