Combining a few recent HN topics. I bet you could reverse engineer a prion to develop the mRNA to create it. Pack that gene into something like SARS-CoV-2 that's highly transmissible but maybe not quite as loud in the body. Let it burp prions into your system while it's humming away then in a year or two a couple billion people die of spongebrain.
I would take that bet, prions are proteins, they don't code for anything, they cause normally-shaped versions of the same protein to re-fold when they come into contact with them.
Sure but they are still made of amino acids and presumably could be translated from some sequence of mRNA. You might need to modify it slightly to provoke the alternate folding while still maintaining the essential infectious/auto-catalyzing structure.
