I had a crab just like that in my TBS order.....it has evil red eyes, looks like a decorator crab, only it doesn't decorate itself.
mine even attacked me, the only crab that has hurt me with its claws
take it out........take it out......take it out
So i put it in the holding cage with the "normal" gorilla crabs....it ate about 3-4 gorilla crabs over night
Then I put that crab in one of my mantis tanks........it ate the mantis...no joking
it was only a 2-3" mantis, but my crab was about 2-3" diameter also
Later I put it in the tank with a 5" mantis, that crab lasted about 3 months, I think my mantis was afraid of it. My mantis lost one of its antenna, and I think it was due to that crab.
Finally I decided to get rid of that crab, I really didn't like it, so i pierced its shelf with one of my cleaning tools. Once mortally hurt, my mantis took care of that crab.