I think the theories of it being an artificial alien probe were definitely more sci-fi fodder. I'd always imagined that an alien intelligence might have seeded

I think the theories of it being an artificial alien probe were definitely more sci-fi fodder. I'd always imagined that an alien intelligence might have seeded every solar system in the galaxy with a probe to monitor for evolving intelligence - but after Oumuamua, I realized it would be far more efficient and reliable to have swarms of them coasting through systems periodically to check on them. ...or maybe both.