Octopuses! Get used to it! (Unless it's pie...)
In an omnipotent sort of way you proclaim that their grasp on the English language is faulty and that they have improperly pluralized the name of the squid of which they are speaking! Like a cat you pounce on their fault to proclaim your logic the more learned and announce to the world that your mind is superior... Well I've got a little bit of news for you; You're wrong!
Well you're not entirely wrong. You probably swiftly pointed out that it mustn't be said "Octopuses" but Octopi and for that you would be mostly incorrect. It can't be said that octopi isn't a word, which it most certainly is, but in any context the dictionary lists "Octopuses" as the plural. (To a lesser extent "Octopodes" is acceptable, but usually only in biology class.) The term octopi is the plural as it would be written in it's Greek origin, which is technically correct. English, however, often pluralizes these words by the rules of English meaning octopuses actually takes precedent.
So now that you are all in shame of yourselves and probably cursing an English teacher or two... I leave you with this image. A simple time when it is only ever acceptable to say it as it is, "Octopi(e)":
Cheers to the English language and the poor people who weren't born into it... good luck my ESL friends...