Type Zero (Ar tonelico: Melody of Elemia)

The first among the liquid metal robots, this monster is pretty weak in comparison to some of the previous Robot-type enemies. However, it's extremely annoying because of being completely immune to physical attacks, so your best bets to getting rid of it are using Song Magic or attack items, since most physical-based skills won't affect it at all either. Its Z-STAB attack has a high critical hit rate, while its P-ARMOR skill increases its defense, so make sure to get rid of it fast too, otherwise it might greatly reduce your party's HP, and take a longer time to kill.