Lol, roll in the rayban shades and gold chains.
I'm not entirely sure what it is though, I'd go along with some of you and say it was perhaps a breathing tool to aid the predator with it's intake of different gases - as the xenomorphs don't rely on Oxygen, what's to say the preds do either? I dunno, who the hell am i anyway, i hate aliens and predators......
Wait...that's not right.
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