What is this claw of?

[Little Cart]

I have seen the claws twice now in 2 months..from the EXACT same crevice in the live rock. Seem to appear when I feed, but they only pick at the rock above it and don't seem to ever grab anything. The other claw is small..typical of a crab. Last night I notice a very thin, tiny leg. The color is pale, almost translucent..and no hairs..very smooth. I wish I could see the body...but I am afraid to disturb the rock/tank.

One pic I included has a Blue Leg Hermit to show some sort of scale.

Any ideas? I am a beginner..only had my tank about 2 years.

 

[Alex]

might be a pistol shrimp....

 

[FMF0331]

Looks like a pistol shrimp

 

[TRIGGERMAN]

oh there's a blue leg hermit next to it I didn't see that at first I thought those blue legs belonged to the owner of that claw. I'm sure that's why the others were saying pistol shrimp because they have blue legs. There is no way to know or even guess without a better view.