Let's play an FF Guessing game. Here are the rules. I ask a question FF related and you must guess the answer. The person that gets the answer right will then ask the question. However, I(or the person that asks the question)must confirm that you have the correct answer, even if you are 100% positive that you have the correct answer. I'll begin the game and I'll start off with an easy one.

This spell started out as a Black Magic spell but then later on in the series it became a white Magic spell. Which spell is it?