“When [Sigur Rós](https://pitchfork.com/artists/3784-sigur-ros/)’ second full-length record, [Agetis Byrjun](https://pitchfork.com/reviews/albums/7151-agaetis-byrjun/), landed stateside in 2001, its extraterrestrial oozing was so unfamiliar (and, subsequently, unnerving) to American ears that it managed to finagle a staggering number of meticulously rendered comparisons to glaciers and fjords and i”