Danny Phantom Season 3 Episode 4

Torrent of Terror

Amorpho, a ghost with morphing abilities, impersonates people and gets them into trouble with it. He then impersonates Danny and both of them must learn the price of fame when a fenton device interrupts some of their powers, preventing Danny from returning to his human self and locking the evil shapeshifter in a shape that calls too much attention: Mr. Lancer's.