Who knows what the song is after POTRE, it could have been an unfinished/unreleased work in progress or just something to play in between
They played that during the Cameron Jamie shows, placed after Pigs just like they did here. Great riff. Might have been a glimpse of future work at the time, before the BB lineup added a new dynamic to things.
After that, Sunn O))) and Boris took that riff and evolved it into the most perfect and evil drone doom song ever, Etna.
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Nah. That just sounds like a cool story, they didn't really do that.
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...
...or did they?