Spring Metal

Spring Metal (スプリングメタル) is a stronger variation of the Emerald Blues Heartless and only appears in Kingdom Hearts II Final Mix. Unlike its relatives, its name doesn't seem to start with a color (but it still has the name of a type of music at the end of its name). The "Spring" in its name could be a reference to the color spring green, though no part of the Heartless is this color.