Final Fantasy X - Earth Eater (Monster Arena)
I decided to only upload the original creations, the other ones are usually nothing special with fairly high stats.
This dude is your only source for Fortune Spheres, so get ready to fight him a lot. He has an instant KO counter, and when he's lying on his back he uses Flare as a counter. Just be prepared to die a lot. Having an Auto Phoenix in this fight is almost essential.
This was my first win against him in this file. I had to beat him when grinding fortune spheres at much higher stats and he was much easier.