There's nowhere to go but down/Hitting the ground running: Bands whose first recording(s) changed everything

Saw Peter Murphy last night for the first time despite being a huge fan for decades. I am always struck by the fact, but never more so than while watching him perform it, that "Bela Lugosi's Dead" - a track that helped invent Goth Rock - was recorded in the band's very first demo sessions less than two months after they formed.

What other examples are there of bands who came up with seminal, archetypal moments way earlier in their career than they had any rights to?

"Upside Down" by the Jesus and Mary Chain comes to mind. Was pretty much the blueprint for the next half-decade of noise-rock, and they never did shake it, no matter which direction they explored.

She had some singles before it, but for Patti Smith it's not easy topping Gloria, first song on Horses.

"But Anyway", the first track on Blues Traveler's début, changed everything. Run DMC first said a DJ could be a band, and the Travelers took that to heart. Instead of a DJ, though, they had harmonica solos. "Dropping Some NYC" was galvanizing: "I've got a little something that I don't think you've tried", sang John Popper, and he meant a harmonica solo. Nothing was ever the same.

https://www.youtube.com/watch?v=q__91ggHuf4

Their first single, started a genre that's still going on 30+ years later.

Pistols Spunk demos

crossposting with the Low thread, but arguably their bedroom demo recording did something pretty close to inventing a style.

"Losing My Edge" seems like a pretty obvious pick here