Appear in the blue and red areas and the surface. Normally they don’t spawn onto you just because you have no charge, they seem to spawn around like normal dinos and are drawn out when you have no charge. This means you CAN clear areas of them for a while at least if you kill them before too many spawn from alphas. Have a light pet with you but have it off to draw them out, then when they emerge turn it on and use a strong mount to kill them off with ease, preferrably the crab. They also seem to take crush damage from big dinos walking over them even when they’re underground (though this may have been fixed). Plant Z fruit can force them underground which could save you in a pinch.