A few clowns short of a circus.
A few fries short of a Happy Meal
A few Cokes short of a six-pack.
A few peas short of a casserole.
The wheel's spinning, but the hamster's dead.
One taco short of a combination plate.
A few feathers short of a whole duck.
All foam, no beer.
The cheese slid off his cracker.
Couldn't pour water out of a boot with instructions on the heel.
He fell out of the stupid tree and hit every branch on the way down.
An intellect rivaled only by garden tools.
As smart as bait.
Chimney's clogged.
Doesn't have all his dogs on one leash.
Forgot to pay his brain bill.
Her sewing machine's out of thread.
His belt doesn't go through all the loops.
No grain in the silo.
Proof that evolution CAN go in reverse.
In the pinball game of life, his flippers were a little further apart than most.
About as sharp as a sack of wet mice.
Dumber than a bag of rocks
The wheel is spinning but the hamster is dead.
He is "special"... in that Olympic sort of way.
When he was in school he got to ride on the short bus and wear his very own helmet.
Not the brightest crayon in the box.