Maggots

there is no creature on this earth fouler than the maggot.

Imagine...

there's one in your ear. A man, braved through the sword, the rifle, the sanguinous blast; he would scream in purest terror. Every muscle would seize up, eyes widen to black. Digust, fear? Which rules over the other? A man should be dead before any such creature inhabits him. Literally.

It's the way they move.