Kill-My-Wife Spray
A spray that needs to be invented by the makers of Raid that effectively kills my wife upon spraying her. This spray would not leave any detectable traces of poison for the CSI team to uncover so I could claim it as a case of SWDS (sudden wife death syndrom).
I would show that nagging pest of a wife when I get rid of her like I did the last one--with a few squirts of kill-my-wife spray when she's sleeping off the beating I gave her.