If you play Faceless Butcher/Mesmeric Fiend and then put it's CIP ability on the stack, then put an ability that would trigger the leaves play ability on the stack, the CIP ability will trigger after the leaves play ability, thus removing a creature/card in hand from the game entirely. Good effects for this are Capsize, Claws of Gix (with recursion), Parallax Wave (Skull of Orm?), and Tradewind Rider, to name a few. You can even tap the Faceless Butcher as part of the Tradewind Rider's activation cost. If you play Recurring Nightmare, you can sacrifice a creature in play (Squee perhaps, so you don't lose card advantage), put Faceless Butcher/Mesmeric Fiend into play, sacrifice it with Claws of Gix as a fast effect and you remove one of your opponent's creatures from the game. Next upkeep, you get Squee back and can start the process all over again. It only costs 3R per turn this way to remove one of your opponent's creatures/cards in hand from the game.