I really want someone to try this and report back. It really does feel like something that could execute.

not the same thing at all, but there's already been a couple of pretty high profile "prompt injection" malware cases out there.

I have asked several LLM to output brainfuck and Malbolge, but none of them seem capable to do so, even those that implement train of thought, me included ofc.

bf was my first thought, but I would think that would be very easy to parse for computers, and hard for humans. So maybe something that's a lot more verbose?