Why are crabs so scary?
Big pincers, no face (not the mammalian eyes/nose/mouth), walk sideways, and even their mother's don't love'm.
They have damn giant pincers, and you don't want to be recalled as Rufus “One-Arm” Grauch.
They're scuttling, armored ambulatory kidneys that'll eat your soft bits.
I always loved the scene with the giant crab in that old Harryhausen Jules Verne movie, “The Mysterious Island.”
Huge freaky-looking crabs can be on the scary side, indeed.