Terminids

The Terminids are one of three current factions The Helldivers can fight against, with the others being the Automatons and the Illuminate. They also have two subfactions: the Predator Strain, and the Spore Burst Strain.

Overview

The ravenous Terminids are guided solely by an instinctive urge to reproduce, spread, and destroy Democracy. They are a fast-evolving plague, a shapeshifting infestation that threatens to devour and disenfranchise every single child on every single planet.
— Playstation Store Description

The Terminids, insect-like creatures referred to as Bugs before their scientific name was given, are swift-moving, swarming aliens. Much of the Terminids attack using their claws and acidic bile. They now swarm the planets north-east of the Sol System.

Acid

Acid, also known as Bile, is the preferred method of dealing damage for some Terminids, namely, the Bile Spitter, Nursing Spewer, Bile Spewer and Bile Titan. The Bug Mine also applies acid to creatures that step on it. Acid blobs deals damage on hit, depending on the size of it, and then applies a slow and damage over time effect.