Whether you’re a metal devotee or your knowledge of the current scene is rusty, Champion Brewing Company’s third annual Metal Showcase (part of the Tom Tom Founders Festival) is the place to exercise your nod and crush cans of brewery favorites as mutant-hardcore and grind noise meet nuts-core metal and power violence in a show that features Suppression, Sete Star Sept, God’s America, Salvaticus and Disintegration.