Their biography is somewhat similar to Spinal Tap's. Massacration started as a fake parody "true heavy metal" band on the comedy TV show "Hermes & Renato" on Brazilian MTV, with fake biography, fake long hair, fake live recordings, dumb interviews and whatnot. Since then, they've done a bunch of real concerts (including a tour with Sepultura, with Igor Cavalera as session drummer), and released an album produced by "Rick Rubinho", a.k.a. Ratos de Porão's João Gordo.
They also became hosts of "Total Massacration", a Headbanger's Ball-like TV show, with jokes in between.