Hard to say, it blurs out when I zoom in. @ISpeakForTheSeas is going to need a closer view, put white paper towel in a shallow bowl, put it in and take a close up. Like I said I’m having trouble seeing but it doesn’t have the black tips at the end of it’s pincers like a gorilla crab and the end looks similar to an emerald crab used for pulling algae.
If you like a good id, get a better picture against a white background preferably.
I would stay on the safe side and put it in the sump if you have one and If not I would just get rid of it. Even the crabs that are commonly kept in this hobby are sometimes not reef safe so I would just err on the side of caution.