The melodic death-metal band Dethklok works on two levels. It began as a fictional group that originated on the Adult Swim cartoon Metalocalypse, a TV show that both spoofs and honors heavy-metal culture and music. However, the success of the series led Dethklok to become a real band that has toured with Mastodon and BABYMETAL and continues to release full-length albums. With music written and performed by Metalocalypse co-creator Brendon Small, songs like “Aortic Desecration” and “Murmaider” boast the type of punishing riffage, growling vocals, and macabre lyrics that rival those of any death-metal band with more traditional roots.