Hello all. I just purchased my first live rock yesterday. I found several hitchhikers already, but could really use some ID help. Let me start with the most intriguing find. Among a piece that has lots of worm or snail tubes (some appear occupied), I found this guy hiding in a crevice. I'm also wondering if these tube are beneficial or if I just started my tank out with an infestation. Any help would be greatly appreciated!