Bouncy Bastard

An extremely slippery type of person who has a way of being so unbearably stupid that you don't understand how they could possibly be a functioning human being.

This term can also be used as a unit of measurment.

John: What's a URL?

Me: What kind of a dumb bouncy bastard are you?

or unit of measurment:

Jimmy: how long do think this bridge is?

Tom: I'd say that it's about 69 bouncy bastards long.