Here is information I found on Gorilla Crabs, hope it helps.
You want to keep a lookout for Gorilla crabs (xanthid species). These pesky buggers are predators that can cause damage to your reef, eating anemones, clams, and anything else they can get their claws around. They might look cute when they're small, but it's just not worth putting them into the tank. If you really want to keep them, you could put them into your sump/fuge (if you have one).
The sure-fire way to spot one of these is to look for the black tips on their claws. As they get larger, they become quite "hairy" all over. Take a look at the catalog of organisms for pictures of other "good crabs" that may hitchhike on your rock.
im thinking it is a gorilla crab. thats the only one that looks like this guy. the tips of the claws are very pointed and black, so im thinkin bad-guy.
agreed. I had one just like it. Was all excited at first because he was a freeby with the live rock, then I was not so excited when I determined what he was.
Sorry
yup.....chitty.....but i do have a 2 gallon tank i used to have a betta in, all ill need to get is a small heater and i can keep him in there. any ideas of anything else i can keep with him in there??