Do crabs burrow under sand?

[lil ape]

I have a crab that i can't seem to find. I don't think it's in it's shell, and i don't know if someone ate it. I have urchin that's on top of it sometimes, but i don't know if it's trying to eat it or if it's moving around it. Does any know if it may have burrowed. I think the name of the crab i the electric blue hermit crab.

 

[sea slug]

somtimes when hermit crabs molt they will bury themselves in the sand he/she/? may have molted. Consider putting a larger shell in the tank for him/her/? to move into.

 

[windmill]

Horseshoe crabs are usually NEVER seen above the sand during the day.
But it's a hermit.....so seaslug is on the right track. It may have molted and doesn't have a big enough shell to move into.