MMMmmmmmm.... crab legs.
As for the hitch hiker crabs: Where there is one, there are many. I have a couple of crabs in my (gasp) reef right now that are the strangest looking critters I've ever seen. I have no idea how I'm going to get them out of there so I've just been hoping against hope that they'll remain model citizens. I do not relish taking apart my reef and moving all of my corals to yank a rock that some blasted crab is held up in so that I can get rid of him... but I've been known to do it.