Yep. I remember one of the Final Fantasy bosses that would heal itself for a massive amount. The first time I fought it, I was thinking I was about to win even though I was on the verge of death, when "9999" or something in green numbers floated up above the boss. Talk about being stunned in despair.
Though a different thing, I remember a boss in one of the Borderland games resetting completely when you got too far away, even though you were still within range of its attack. I almost turned the game off when that happened.








