Well someone else mentioned llama.ttf which is a font that embeds an llm, using Harfbuzz's WASM engine.

So, you could absolutely write a WASM Z80 emulator and embed it in a font. Whether or not you could make it do anything useful, or how strong your grip on reality would remain after? I don't know.

But it wasn't like you were doing anything else on the days between Christmas and New Year, right?