Sephiroth (Final Fantasy VII boss)

Sephiroth is a boss in Final Fantasy VII. After defeating Safer∙Sephiroth, Cloud Strife falls into the Lifestream and fights a metaphysical Sephiroth inside the spiritual realm. This boss battle is completely cinematic, as evidenced by how all his stats are 0. Cloud will instantly gain the Limit Break Omnislash even if he has not learned it from Gold Saucer's Battle Square. If Cloud does not use Omnislash, Sephiroth will attack Cloud, to which Cloud will instantly counter and win the battle. It is impossible to lose.

It should be noted that if cheat devices (such as Gameshark/Action Replay etc) are used to keep the player's Materia, one can use Sense on him to find out that Sephiroth has 10 Hit Points.

Trivia

 * Cloud has a different, more detailed battle model in the fight that is only used in this one battle. His face is more detailed and he has studs sticking out of his shoulder pauldron.
 * While it is impossible to get Game Over in this battle, it is possible to hang the game in an infinite loop via a cheating device. If one is to set something else than a weapon as Cloud's weapon (say, a Protect Ring), Cloud's regular attacks will miss. When Sephiroth slashes Cloud and he counterattacks, he will miss, and Sephiroth will keep on attacking Cloud but his every attack deals less and less damage, until he is doing 0HP damage on every hit.
 * Unlike the rest of the game, Sephiroth is barechested in this fight.