One who makes a point to say the most rediculous things at the worst possible time, often to the listeners misfoutune. It is always part of a Dousche Magousch's plan to use this to get a promotion, gold star, etc.
The talk with the boss was going fine, until Richard poked his head in and said, "you forgot to clock out last night!" I was fired. Richard is a fucking Dousche Magousch.