Danny Phantom Episode 28-29 - The Ultimate Enemy Episode Title:The Ultimate Enemy.Episode Description:Danny is desperate to pass a standardized test called the C.A.T. After a fight with a ghost from the future sent by the mysterious Clockwork puts the answers to the C.A.T. in his hands, he decides to cheat in hopes of securing an easy pass to a great future. After fighting another ghost from the future, he, Sam and Tucker discover that Danny cheating leads to a horrible future where after the death of his family and friends, Danny grows up to be Dan Phantom, the evilest and most powerful ghost on the planet who terrorizes the world. Upon discovering Clockwork's interference, Dan tries to make sure Danny's horrible future comes to pass. To save his friends, family and future, Danny must dig deep and do the right thing to ensure he becomes a better man. At the end of the episode, Danny finds out Jazz knows he is a ghost.