Burzum/YMMV

Draco in Leather Pants - Some people believe he killed Euronymous in self-defense (as Varg himself claims).
I Liked It Better When It Sucked: Sort of. In 2011 Varg released From The Depths of Darkness, an album featuring re-recorded versions of his favourite tracks from the first two albums with more professional musicianship and production. Critics and fans alike reacted less then favourably - the consensus was that the raw performances and shoddy production on the original versions of the tracks in question was a large part of their charm.
Memetic Mutation - From the song "War":

"This is war... huh... wow."

- Note that this is probably a Mondegreen; it's generally agreed that Varg is actually saying, "This is war." But with his strong Norwegian accent, it's hard to tell for certain.
- Also, the Burzum parody project Bumzur basically exists to create Burzum memes.
- Hell, Varg himself is a meme.
Narm - See Memetic Mutation above (with regards to the song "War").
- Also applies to his style of screaming in general, although YMMV. Some find it to be quite frightening.