I fought with psi-beetle, and cornered him into rocks.
When he stand there, I can't do any damage to him.
Don't know is it complete invulnerability, or he just get resist somewhere while stand here.
I fought with Combat Gloves, two turn he took 0 damage, after he moved from there, he start to take damage as usual.
He stand where pointer is.
This is location, where entrance to Newton's location is.
Upd: Errrrr should I post it in "0.1.14 bugs" topic? Sorry.
___________
Wait! Is it possible, that psi-beetles have lower damage treshhold while theirs brains exposed? And while not, they are more armored?
If so, it's false alarm.