1800 years ago, during china's three kingdoms era, there was a warlord named cao cao who was extremely ruthless, cunning, and backstabby. in english, we say "speak of the devil and the devil arrives," but in chinese, they have the same exact saying, it's just that cao cao is the devil. however, he was also recorded to suffer from terrible headaches, and eventually died of a brain tumor.
anyways so it became a meme on the chinese internet to leave ibuprofen at his grave