I think that’s a Thiel thing. Tolkein was was one of his obsessions growing up. It doesn’t surprise me that he saw a plot device intended to be a warning as a really cool idea…

That sounds like an XOR pointer, which did used to be a standard feature in Windows. There were patents on it and xorg were threatened with legal action by the patent holder, so I don’t think it was ever added to X. Those patents have probably expired now, so it may be possible to do.