Ok, so... I'm playing Persona 3: FES edition... and I'm on the final boss, Nyx Avatar.
It was pretty rough battle, and I was almost ready to finish him off and end the game. This was long and excruciating, and I was running out of supplies. However, the boss only needed like one or two attacks and then he would die.
Time to be happy, right?
I made one error (I forgot to guard), and my team suffered for it as they suffered a massive attack that drained most of their life.
However, I had a character who had Diarhan, which essentially ALWAYS heals a person up to their max hp.
So, being the awesome AI he is, he decides to cast it.
However, before it is his turn, the boss does this move which CHARMS the healer, which means whatever action he was going to do was going to be in favor of the boss.
So what does the heal do? HE HEALS THE FINAL BOSS ALL THE WAY UP TO MAX WITH DIARHAN.