The third season of the animated show Metalocalypse originally aired on Adult Swim from November 8, 2009 to October 24, 2010 with 10 episodes. The show follows virtual death metal band Dethklok. This season featured a 21 minute runtime.

The fourth season of the animated show Metalocalypse originally aired on Adult Swim from April 29, 2012 to July 15, 2012 with 12 episodes. The show follows virtual death metal band Dethklok. This season returned to the original 11-minute long episode format. The season four DVD/Blu-ray was released on October 30, 2012 through Adult Swim/Warner Home Video.

Dethklok is the biggest, baddest, and most famous heavy metal band in the world. The quintet, consisting of Americans Nathan Explosion (vocals), William Murderface (bass), and Pickles the Drummer, along with Scandinavian guitarists Toki Wartooth and Skwisgaar Skwigelf, have to deal with their fame and other situations in their lives, all the while being monitored by a government organization out to destroy them.