How to ruin the internet by putting down a few symbols 2,000 years ago.
First, go to a modern dig site in Pompeii , find an area that was uncovered today or a few days ago. Travel back in to early august or late July in 79 AD with a pickaxe and stone carving tools. Carve into the stone the numbers “1•2•2•50” make sure they are in Arabic numbers to confuse archaeologists.
This will explode in the history community and in the meme community, then fester into almost every other community.