Star Ocean III: Till the End of Time Tips

Use rabbit ears chalice
Doing Roger's Ancient Book Sidequest will give you an item called the Rabbit Ears Chalice in the Ursa Lava Caves.

Have the item equipped during battle and enter: UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, (CIRCLE X or X CIRCLE, depends on refinement).

Your character blow up and deal damage to the enemy