That alien guy from part 4.

I just thought about it, couldn't that be Cars? Maybe he lost his memory or something when he came back to earth.

Evidence please.

It's just a theory. I'm re-reading part 4 and it just came to mind.

I'm basing this on the fact that the alien guy can shape shift and doesn't have an actual stand. Plus, Araki didn't bother to write him a story about his past, only that he fell from the sky.

Oh yeah, and since he's immortal (The Red Stone) he doesn't die while in the sun.

Actually he sort of does have one or at least a name for the ability.

"Earth, Wind, and Fire."

And in all honesty Cars couldn't have landed back on Earth at that point it's physically impossible, the only time he could actually come back to Earth is with Planet Waves and that happens in Part 6.