If you're a fan of the hit new television show Duck Dynasty, then you know not to mess with Si. He will hurt you physically and metaphysically! If you're a fan of Si Robertson, show it off with pride. This officially licensed Duck Dynasty t-shirt features one of his more memorable lines from the show, which makes it an excellent choice for any die hard fan. With this Si Robertson t-shirt, you can let the world know that you aren't messing around, Jack!