Here's an interesting glitch. When you kill an enemy (or when an ally falls), they turn into a Crystal after three full turns. You can then pick up the crystal, which will usually result in a restoration of HP and MP for the character who grabbed it. Sometimes, however, skills and abilities can be learned from the Crystal. If this happens and there are multiple options, always choose the last skill listed. Your character will then learn all of the skills and abilities listed, not just the one you selected.