A large crab leviathan

What if there was large crab leviathan but it’s like a Tran door spider (if you don’t know what that is it’s a spider that burrows and uses its environment and silk to make a trap door and it sets mini trip wire to sense prey then pounces on it)but that is the whole concept of the great crab leviathan and you could see unsettled sand were the trap door is and you can also hear little clicking sounds

ew no pls no spiders :(