In Mario Kart, red shells target your nearest rival and ruthlessly stop them in their tracks. Marketing company Red Shell, meanwhile, helps video game companies more accurately target you. This fact has not sat well with some players who have recently discovered the software in a veritable kartload of Steam games.
We're conditioned to expect console manufacturers to be bitter rivals, constantly at each other's throats in a battle for market supremacy. But sometimes, the enemy of an enemy can be a friend.