"Join me, and take the world for yourself!"

Fathom Fleet Captain

Menace
Whenever this creature attacks, if you control another nontoken Pirate, you may pay {2}. If you do, create a 2/2 black Pirate creature token with menace.

The Lost Caverns of Ixalan Commander

Menace
Whenever Fathom Fleet Captain attacks, if you control another nontoken Pirate, you may pay {2}. If you do, create a 2/2 black Pirate creature token with menace.

Ixalan Promos

Ixalan

If you don't control another nontoken Pirate at the moment Fathom Fleet Captain attacks, its triggered ability won't trigger. If you don't control another nontoken Pirate as that ability resolves, you can't pay {2}.

While resolving Fathom Fleet Captain's triggered ability, you can't pay {2} multiple times to create more than one Pirate token.