Crabs, yes.

And I don't know what a mazoku is, so they could be? Maybe? I haven't fought them myself, so all I know from word of mouth is that they're vicious little monsters that are apparently about as big as a large dog, who dislike the light, live mostly in the underground, and bite people. Apparently they can be killed, and it's recommended that you be armed, since being bitten is apparently a not so good plan.

... Are you sure you're okay by yourself? Just double checking.