Okay, the X-15 was pretty great, but speed alone doesn't make it "the baddest airplane the world has ever known". When I read the title, I immediately, unhesitatingly assumed it would be this: https://en.wikipedia.org/wiki/Gee_Bee_Model_R.
Yeah, calling the X-15 the most badass plane ever is a bit silly. If it counts, then why isn't the Space Shuttle "the most badass plane"? It went faster & higher, after all.
Anyway, I'd assumed it was going to be the SR-71, but yours looks awesome & I enjoyed the article either way!