We got some of those in at tpa a month or so ago and like cml800 stated they do not transit well. Cool fish, but a little risky. We can order them in for you if you want to roll the dice tho.
My first reaction was nassarius. But if its definately not one then my second reaction would be a conch. I've seen mine scale the sides of my tank befor, it takes them a long time, but never underestimate the determination of a bored/hungry invert.
Your corals will be fine for a week or so without light, I had really bad cyano once and left the lights off for a whole week and everything was fine afterwards.