The JAR METHOD:
For rogue crabs in particular... this is a fab, cheap and easy way to grab the critters.
They generally have very pointy "toes." This aspect of their legs makes them very well adapted to hold onto rocks, corals and other hard substrates in particularly heavy water flow on the reef. They can exploit places to hunt for food or graze algae, etc well by this adaptation.
But they cannot climb glass
Have you every seen a hermit crab hanging front and center in the middle of your aquarium pane? Ahhh... no.
And they cannot climb the glass walls of a pickle jar, or the like, either.
But they CAN scurry down to the bottom of the jar after some favorite stinky, smelly meaty foods
And they will be waiting for you to pull them out later
If you have other creatures in the tank that will also go for this bait... deal with it. Finesse the "trap" or the hunt as needed. Bury a smaller jar in the sand, lean it against the rosk, narrow the mouth or opening to reduce the number of tankmates that are small enough to enter... hunt at night for an hour or two after the lights go out so you can watch, learn, adapt, etc.
Be creative.