Elemental Fury (6th)

Elemental Fury (Su; acid, cold, electricity, fire, radiant, sonic): You must select one type of energy: acid, cold, electricity, fire, radiant, and sonic. Once this choice is made, it cannot be changed. You can expend 1 point from your Ki pool as a swift action to imbue your natural attacks with this energy, causing them to deal 1d6 points of damage of the chosen type for a number of rounds equal to 1/2 your monk level. A monk must be at least 6th level before selecting this Ki power.