About half a decade ago or so there was a manga series I was following that was by far the strangest thing I ever read.

So this series was like the definition of mindfuckery. I only remember specific bits and pieces, but if I remember right, it started off normal. I think the protagonist was narrating how bland life was. Everything was the same at school. Boring. But there was this female classmate who was weird but nobody seemed to care, and she told him that everything was a lie or some such? Nothing was real. And from then on stuff got weird, and it turned out she wasn't this crazy oddball.

I think the protagonist got injured at some point and his skin was torn and it turned out his body was a machine, all metal and wires. I think this series took that one Descartes saying too literally in doubting everything you know, and was basically about how everything's a lie.

That's about all I remember. I don't think I read much, either because it was an ongoing series at the time or I just didn't get far enough back then.

This?
Classmate, Kamimura Yuuka wa Kou Itta

Yeah I know my english is bad

Yes, thank you! Funny, I don't remember it being so obscene. 🤣