Is Iron Man a trademarked name? If so (and I think so) then the rules regarding pluralizing trademarked names (recently in the news regarding iPod pluralization, most grammatically properly “multiple iPod devices” rather than “iPods” ) may apply. Trademarks are properly handled as adjectives. There are various depictions of Iron Man characters on that shirt. The fact that it is handled as a noun within the fictional universe is immaterial to how it is handled within the real world. Within the fictional universe pluralization is up to the creators or perhaps the characters, be they Proudfoots or Proudfeet.
Yes, Superman has all his characteristics regardless of how he’s dressed or what he’s called. But no, Tony Stark is not Iron Man out of the suit. He can’t fly, he can’t bear most attacks, he can’t fire repulsor rays. It’s not clothing, not even “very special clothing.” It’s an integral part of the entity known as Iron Man.
Movie-schmovie, I disagree. Stark is certainly the human portion of Iron Man, but he alone is not Iron Man, and the suit is much more than just a prosthetic (see above).
When they finally decide Robert Downey Jr is too old and replace Tony Stark in the movie universe, they should have a scene in the movie where Tony announces his replacement by standing next to him at a press conference and announcing, “We are Iron Men! No, wait. We are Iron Mans! Iron Mans or Iron Men? We are Iron Men? That doesn’t work either. Wait, I got it. I AM IRON MAN! AND SO IS HE!”
I wouldn’t say “Batmans” or “Supermans” either. Same problem.
The bottom line, as alluded to above is that we shouldn’t expect absolute consistency, and BOTH constructions just SOUND wrong. In practice, I’ll weasel out of it by saying “Iron Man suits” or something like this. And “Iron Man’s suits” also sounds wrong. “Iron Man” is a modifier for the type of suit. I wouldn’t say “Boy Scout’s uniforms”, although I suppose some people might.
However, for a group of participants in the triathlon event, I would say “Ironmen” without hesitation, as everybody else seems to.
BTW, that “computer mouses” thing never seemed to take root, thankfully. Many dictionaries considers both correct, and “mouses” sounds too close to a Tom and Jerry cartoon (“meeses”). Computers have “mice”, IMO.
When the grammarians aren’t able to reach a conclusion, give up on them and trust your ear.
Generally, I assume that a compounded structure that contains an irregular plural, reverts back to regular plural form, if it does not make literal reference to the noun’s thingness. Like the Toronto Maple Leafs (who are hockey players, not botanical appendages), but a yard full of maple leaves. This is not restricted to nouns. A baseball players flied out to center field – not flew out, which would have a whole different connotation. But I’ve noticed more and more commentators nowadays saying “flew out”, so I guess the pedants must be putting their feet to the fire.
So if an Iron Man is a shirt, and there are two shirts, they are Iron Mans. When I was a kid, our house had a furnace in the basement made by Iron Fireman. Lots of people had Iron Firemans, it was a popular brand.
I mean…ah, fuhgeddabout it. 