Memes

You do have the benefit of being right though.

The word octopus is a classical Greek word that comes to English via Latin. The Greek plural is octopodes, the Latin plural is octopi. But we don't speak Latin or classical Greek. We speak English. Because octopus is the English word for octopus it follows the English rules for pluralization, which is to add "s" or "es" to the end of the word. Cases can be made why octopi and octopodes could be technically correct, but for English speakers octopuses is the most correct.