As the 80's drew to a close, MTV began expanding its programming beyond just music videos. The network had added a weekly countdown show and a daily viewer request countdown, the latter of which was heavily in favor of the then sub-genre of "hair metal". The news department moved beyond having the VJ's read news headlines, as that assignment was given to veteran journalist Kurt Loder.
The news division was also responsible for periodic specials such as Rockumentary, which bowed in 1989, and lasted nearly a decade, mostly with Loder serving as narrator. This was basically Biography, but specialized for music fans. Not only that, but it can be argued that Rockumentary was the forerunner to sister network VH1's long running Behind The Music, which was a weekly series as opposed to, say, monthly, as Rockumentary seemingly was.
The early success of Rockumentary made it ripe for parody, but while I'm not entirely sure if Saturday Night Live or MadTV took a poke at it, the popular NBC Saturday morning teen-com, Saved by The Bell, did an episode during the 1992-3 season that presented the series regulars forming an Archies-style pop group, with radio & cartoon legend Casey Kasem as guest host-narrator. We'll pull that episode of Bell for Saturday Morning Archives another time.
For right now, let's take a look at a bio on Metallica, first broadcast in 1992, but this is a rerun from around the time Beavis & Butt-Head were given their Christmas show.