Celtic's mask & the original mask (jungle hunter as some call it). Celtic's mask was bad@$$, full of detail & awesome looking patterns & curves, without doubt one of the best yautja masks seen so far. Pred 1's mask was awesome too, the aged look of it was awesome & much cooler than the flashy shiny mask of scar that looked like it had just been powder coated. As for the second jaws piercing the mask well, xenos jaws are very powerful, strong enough to punch through metal with ease, but partially like I have said before, I think it was just the way anderson wanted it to be. He wated to make aliens jaws look stronger than they really were. In resurrection when the alien fires his inner jaw at the bulletproof glass it didn't even make a scratch, & in pred 2 the mask withstodd assault rifle shots with ease.