The Neo-Soviet marine biomods
Classified as a category 4 threat, the Elib is somewhere between a vampire lord and Godzilla for limits of escalation. Yes, I would consider using a nuclear device to kill just one. I am that sure that I want it dead.
Beware of towns afflicted with Time Cancer.
For every second you progress through time, an infected town goes back 48 hours. Old buildings slowly become new, then incomplete, and finally just a frame and foundation, giant old trees turn to saplings, birds hatch into eggs.
one must not linger in a chrono-cancerous village for too long, before you know it you'll be a fetus. Tme cancer in unstoppable, no cure or treatment is knwn, it eats through the past until the inhabitants of a village turn into primordial protein ooze