Word "men-of-war" - singular or plural?

[Nessie]

Hi,

Men-of-war is a form of jellyfish with poisonous parts that are capable of doing serious harm to swimmers who aren't taken to a hospital right away and don't get medical help quickly

=> Which is wrong and why? Should "men-of-war" be understood as kind of jellyfish and therefore be used with singular verbs, or should it be used with plural verbs because of the form "men" (not "man"?

Many thanks
Nessie
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Sorry seems to be the hardest word...

[Prezbucky]

singular = man-of-war (Portuguese man-of-war)
plural = men-of-war

"This man-of-war has sharp teeth and straight hair."

"These men-of-war have formed a gang."
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[Nessie]

Thanks a lot, Prezbucky.
By the way, have you any idea why they call those jellyfish "men-of-war"?
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Nessie]

[Prezbucky]

I was joking about their attributes. hehe
_________________
Billie Jean is not my lover. Hee.

[Nessie]

But... I still don't understand, Prezbucky, is your joke about human or jellyfish? :O:O:O
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...