I think it's time to tell the answer, it's just too hard to figure out^^

A weird color mix
resulting unlogical
from almost half-beast
and mushroom colossal

The first two lines are connected. Together, they point to the fact, that when you're mating two chocobos, mostly a completely unlogical color is the result. I mean yellow + yellow = green/blue, green + blue = black?
The fourth line refers to the gold saucer, or even the wonder square, as the gold saucer is a giant golden mushroom in the desert (and the squares are also shroom-shaped platforms?)
And the third line was actually referring to Vlakorados. Number of the beast is 666, half-beast is 333 and his HP are 33333. Follow me?

So the answer was Carob Nut, as the color mixes from it are unlogical and you can get it from both Vlakorados and Gold Saucer (no, chocobo racing was not included in the riddle^^).

seiferalmasy2, your turn.