O'reilly
A word for someone who is as dumb as a sack of bricks. You can only use it after they do something so stupid it makes your brain hurt.
He said the moon was made of cheese, and that’s when I called him an O'Reilly.
She said gravity was a myth and got called an O'Reilly.
He tried to fly a plane with a spoon and got called an O'Reilly.