Looks like a common hairy crab or a brown hairy crab.
In my experience though, if the crabs is hungry, it may nip at small polyps on SPS, regardless of the species.
Thanks guys. I'll catch him tonite. And thanks to my wife, she was the "founder" of this hairy guy. Ehehe
Oh, the feather, I found 1 and now 2, dont tell me this thing grow that fast