Should this special attack be causing damage with zero vit damage or prior wounds to the affected areas? It lead to the wounds below immediately. Subsequent hits with the special do zero compounding damage. However, if you do get an internal bleeder to one of the affected areas, it will continue to push the bleeders to the next level.

A hulking Xala'shar archer draws a hand through its tangled mane of hair and softly says, "Let us even the odds, shall we?"
With cunning movements, several of the blue-veined tentacles lash violently outward at you with a quivering hiss of delight!
Moving a moment to late, you are unable to avoid the barrage of wildly flailing tentacles. Their diamond-shaped heads slam viciously into your hands, arms, and torso with frenzied blows.
[You're nimbly balanced and in strong position.]

Your body feels at full strength.
Your spirit feels full of life.
You have minor swelling and bruising around the right hand, minor swelling and bruising around the left hand, minor swelling and bruising in the chest area, minor swelling and bruising in the abdomen.

Yeah, but being serious and not worth hunting are two different things. They teach great, but bypassing vitality and just causing damage, which will cause stuns on subsequent hits, makes them not worth the effort. The few times I went in there I was the only one there. Besides the insane climbing in and out, this would just stop me from hunting there all together.