Octopi, octopuses, and octopods are all valid pluralizations of octopus in American English.

Conversely, cacti is the only valid pluralization of cactus.

Don’t worry, language itself pissed us off long before you did.

I feel like any linguist upset by non-prescriptive language needs to maybe reconsider their life choices. Imagine telling someone they’re painting incorrectly or being mad at the discovery of a new species.

octopiussi

Linguists are probably the least likely people to get upset at someone using the “wrong” word. they might pull out their notebook and start asking you questions though