Pig Destroyer will be celebrating the 20th anniversary of “Terrifyer” during a headlining show at the Black Cat in Washington, DC. The concert will be held on November 14 and it will also feature Mammoth Grinder (“Undying Spectral Resonance” EP release show), Genocide Pact, and Entrail Asphyxiation. The 20th anniversary edition of “Terrifyer” and “Undying…