the absolute winner of this category is Phantasy Star 4.
Persona 4 also qualifies, but not nearly as big a gap as PS4 has.
also should i assume this is referring to the general boss battle theme *only*? and not to special themes for some bosses? 'cause that'd open the door for quite a few more, though half of that would be because there isn't really a 'boss theme' but goes for each character. though so many said in here are so, so wrong.
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The King Wang.
Listen up Urinal Cake. I already have something that tells me if I'm too drunk when I pee on it: My friends. - Colbert.