Apologies I'm not able to get a photo because it retracts at the slightest hint of movement from me (I have to stay still for at least 30 seconds before it sticks out), but in my refugium, I have seen some sort of arms/appendages with hair/feathery material attached to them, sort of tan/sand colored, sweeping out from under a piece of live rock, sort of sweeping/pushing sand, sort of like digging but not as extreme. I want to say the appendages are .25" or so at most. Any idea what sort of crab/shrimp critter this might be attached to? It would have been a creature that came as a hitchhiker on TBS live rock. I do know that a small (.5-1") mantis shrimp was included initially, but I haven't seen him in over a month. More curiosity than anything, if you have any suggestions with photos that would be cool!