Bile Titans
The Bile Titan (or "Gareth"), the worst of the lot and arguably the worst thing the Terminids as a whole have yet to throw at us. Its fast, well armoured and has enough bio-weapons within its gut to completely wipe a SEAF Platoon or reduce a Bastion tank to molten slag in seconds. Its primary methods of attack is regurgitating the same caustic waste Bile Spewers are known for, albeit now at both far greater ranges and concentrations as well as simply slamming their massive legs onto any target they deem offensive enough. It fortunately has its abdomen sacs exposed much like the rest of their kind, but unlike the rest bursting it won't outright kill it or even bleed it out sufficiently, necessitating the entire destruction of its underbelly to do the job. The Ministry of Defense recommends engaging if one has access to either heavy orbital ordinance or a sufficient replacement budget, personally i would instead suggest a better option: run.
While since determined to not be lethal, destroying the belly sacs of the Bile Titan does disable its ability to vomit toxic waste, allowing them to be better controlled when they do show up
On the contrary, they will often stand still when vomiting, leaving them open to a well-timed stratagem which can outright kill if aimed correctly.
Planning aside, a quick shot to the head with our generous list of Anti-Tank Stratagems is also sufficient to dispatch these monsters once and for all