Danny Phantom - Season 3 - Eps 5: Forever Phantom
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.
About Danny Phantom

Title: Danny Phantom
First Air Date: 2004-04-03
Last Air Date: 2007-08-24
Status: Ended
Rating: 8.3/10 (from 1101 votes)
Language: EN
Seasons: 3
Total Episodes: 49
Network: Nickelodeon
Genres: Action & Adventure, Animation, Comedy, Sci-Fi & Fantasy
Production Companies: Billionfold, Nickelodeon Animation Studio, Nickelodeon Productions
Synopsis
Danny Fenton was once your typical kid until he accidentally blew up his parents' laboratory and became ghost-hunting superhero Danny Phantom. Now half-ghost, Danny's picked up paranormal powers, but only his sister, Jazz, and best friends, Samantha and Tucker, know his secret. Danny's busy fighting ghosts, saving Casper High and hiding his new identity all while trying to graduate.
Cast

David Kaufman
Danny Fenton / Danny Phantom (voice)

Grey DeLisle
Samantha 'Sam' Manson (voice)

Rickey D'Shon Collins
Tucker Foley (voice)

Colleen O'Shaughnessey
Jasmine 'Jazz' Fenton (voice)

Rob Paulsen
Jack Fenton (voice)

Kath Soucie
Madeline Fenton (voice)

Ron Perlman
Vice Principal Lancer (voice)