Help ID please?

[andsoitgoes]

k - I know I have hydroids at the end of this rock, I'm going to chisel it off one day very soon, but I saw something.......... odd today.



I know I've seen pics of them before, but I'm darned to remember where. Here's a few more pics:



This is the clearest picture of this thing - THIS one snuck away not long after the lights went on, the other is still standing its ground:



Now - on a less evil note, I found this guy from my OA trip to by some nassarius snails, I got one hermit on accident!







Anyone know what kind he is?

Please ignore the cyano in the tank, it's not really there, it's uh, just stopping off...

probably on its way to MY reef tank. Jerk of an algae!!