I prefer “platypussies”. 
Platypussy would make a great James Bond villain.
“Down Under”, of course.
No it isn’t. It’s a correct Greek plural.
Now I got The Shoop Shoop Song stuck in my head. Thanks a lot.
While it is derived from the Greek, it is also the correct Latin plural.
From the Staff Report I linked to above:
If you contend that “octopodes” is incorrect in Latin, what is the correct plural?
He was, I think, making the point that it is not a Latin but a Greek word. However, that’s ignoring the rule, older than the English language, that says that the proper plural of a Latin word borrowed from Greek is its Greek plural.
However, what he said was was that it was not a correct Latin plural, which is incorrect.
Live by the nitpick, die by the nitpick.
And I have it on the very highest authority (the late, great Dr. John Ostrom himself) that the large skeleton in the dinosaur hall of Yale’s Peabody Museum is named “Emily.” He told that to my daughters once when we ran into him at his job. One of nature’s true gentlemen.
Yes, but now they’ve changed its name to “Judd.”
(This joke is so obscure that it’s basically a riddle, but I have faith in the Dope…)
A group of platypus religious leaders with total power would be plenipotent pontifical platypodes.
And to be of no help at all, from an australian who has seen them in the wild; I’ve never seen more than one at a time together (in central gippsland) and know no one who has, so there is no practical need for a plural form of the word platypus. So I guess this is mostly an exercise in english langauge usage 
But have two people seen one at the same time in different locations? If not, perhaps there is only one of them in all of nature.
As for moose, up here the plural is “nuisances”.
The Taronga Zoo in Sydney uses the same word for the singular and the plural. http://www.taronga.org.au/taronga-zoo/our-animals/view-by-continent/australia/platypus.aspx
Another plural conundrum: why mouse/mice, but not spouse/spice or house/hice?
“Mice” and “houses” are left over from Old English mys (an irregular or i-umlaut plural) and husas (a regular plural). Early Old English may have started the i-umlaut thing as a result of merging Celtic and Germanic dialects, but I don’t know exactly why or how.
As this comment explains, “spouse” entered English not from Old English but from French, so it got a regular plural.
And finally, you can count yourself lucky that English plurals are no more complicated than they are. There used to be another Old English plural form that consisted of adding a final “u” to the singular. E.g., one ship, two shipu. No kidding.