If you're in early game and planning to run the south cave and snatch the hunter artifact, these things are the ones to worry about. They will absolutely obliterate your puny hide armor and even flak doesn't stand a chance and even worse, like every other cave dweller, they can knock you out. I play on mobile so if you play on PC, watch out for megalania (komodo dragons that give you covid and ambush you from the cave ceiling) i have a primitive shotgun and i mainly fight with my carno in the cave and i haven't tried fighting them with a carno but im pretty sure a strong carno or bary can take on an arthro. i took care of 2 arthros with a shotgun and a primitive shotgun deals 64×10 damage (640 damage total) and the shotgun is a double barrel so

640 × 2 = 1280 damage. so the shotgun is your best friend in the caves to deal with spiders, scorpions, and other cave dwellers. good luck stealing the artifact!