As a native greek speaker, I find anything other than "octopuses" to be silly. In greek we don't say (any more) octopodes, we say "chtapodia" (the "ch" is the canonical (ELOT) transliteration of the letter χ).

Just like meese is the plural of moose

I actually love octopods. Somehow sounds the least weird of them all.

Level 10: all forms are valid as long as enough people use them. The currently most used forms are octopuses and octopi, both valid, but octopi is malformed, so octopuses is preferred. Octopussses and octopii and rare variants of those. Also correct, but rarely used.
Octopodes is also correct, but considered pedantic.

Level 11: Just use what you are used to.

Octopodes, pronounced oc-top-o-dees, not oc-to-po-des. Like Hercules.

Also, using the I ending to pluralize us endings comes out of an attempted prescriptive reform of English in the late 1800s to make it more like Latin. We still use es endings to pluralize us singulars most of the time, the places where we use I are ether direct usages of Latin words or remnants of that prescriptive push.

Confused Squidward noises.

Your prof is Roger Moore?

One of my favorite things in life is using Latin or Greek plurals on words that it makes absolutely no sense to use them on, and do not follow the rules of any language naturally involved.

I had steak and potati for dinner last night. Just one steak, though, I cannot eat multiple steakices

I always say 'I saw some octopus'

Also, moose is plural for moose.

2π: two pi

π: one pus

I thought it was octopuxen?

Octopodes nuts

Its whatever your heart is telling you.

I do like octopods. I will use that from now on and you can't stop me.

American English: "All of the above are valid."

"Even 'octopussies?'"

American English: "...sure."

2 octopus = 1 hexadecipus

Octopoden!