Quina would try to eat the mound of dirt. The dirt would be full of little grubs that Quina is allergic to. S/he would belch out the dirt and the grubs would attack him/her for disturbing them in their home. S/he would run off in terror. The mound of dirt remains.
Yuna would win because she would summon a really big Tonberry of DOOM!!!
Quina VS a mound of dirt.
I wet myself here, so very funny