DamonTarlaei is a great example of a little knowledge being a dangerous thing. He claims to be a Latin 'scholar', yet does not know that 'octopus' is of Greek origin. The 'correct' plural, therefore, is 'octopodes'. However, 'octopusses' is generally accepted these days. The one plural that is absolutely wrong (always was, always will be wrong) is 'octopi'.