Too dumb to pour piss out of a boot with the directions on the heel.

So bad Hell won't take him because he'd take over.

Too dumb to pour sand down a rat hole.

Couldn't find his butt with both hands, a flashlight, a map, and a mission statement.

Stinks bad enough to drive a buzzard off a gut wagon.

He'd steal his mother's pension.

Crookeder than a dog's hind leg.

Mean enough to kick a new-born puppy.