What is with the Meatsack enemies in the necro-settlers league?

Do they just take no damage at all or is there a special strategy you're supposed to use?

They are very tanky with high life - just keep at them or ignore if you can't kill them. My witch had to dispatch a cold resistant one with her default wand attack in the Mud Flats! It took ages. It also didn't do her any real damage.

If you see more than one at a time, then keep moving and avoid them if possible.

Stygian Spire in The Ledge will teach you some lessons.

They are just grooming you for poe2