Dr. Rockso is a rock 'n roll clown. He does cocaine.

Part way through the first season of the show, the band became endorsed by EMG pickups. Later episodes were changed to reflect the endorsement, with all pickups on the guitars and basses being changed to EMG. However early episodes and the show's intro remained the same, with the guitars and basses using the original stock Gibson pickups.

The series creators had the final designs for most of the band members finished when the show went into production, except for Pickles, who went through twenty or more design concepts before finally settling on the current character.

The name of the grocery store in the first episode is "Fintroll's" a reference to the Finnish folk-metal band Finntroll. Other references to metal bands include the restaurants "Burzum" and "Dimmu Burger" (as a reference to "Dimmu Borgir") the outdoor store "Marduk's" and the hardware store "Gorgoroth".

The series was originally named Death Clock Metalocalypse. Due to the name "Death Clock" already copyrighted, the name was then changed to Dethklok Metalocalypse. To prevent confusion the name was then shortened to Metalocalypse (the band is still named Dethklok).

Dr. Rockso's real name is Leonard Rockstein

Dr. Rockso's videos were banned from music television because you could see his "junk"...through his jumpsuit.

In the first scene of the season 3 premiere, the members of young Dethklok appear signing on their record label. All the members of Dethklok are there except for Toki Wartooth, who has been replaced by an older looking person. Later, his name is revealed to be Magnus Hammersmith, who was fired after he attacked Nathan Explosion with a knife, and eventually replaced by Toki.