Melphyx (Upper Body) is a boss that appears in the Sunken Desert in 600 AD. Along with Melphyx (Lower Body) and Vilepillar (Hexapod) it's defenses are lowered when struck with Water or Ice Magic (Although it is immune to damage from Water/Ice Magic). However, when struck with a physical attack, it's defense increases. In order to maximize damage, you must strike it with Water or Ice before every physical attack. Ayla, Crono, and Robo are able to do the most physical damage per strike, so having at least one of them is a must. However, do not forget to have a Water/Ice Magic user, otherwise the chances of winning are very slim, even at higher levels.