The New Adventures of The Wild Thornberrys: Invasion of the Thornberrys

Alien's Power is the one-hour special in the sixith season of The Wild Thornberrys.

Summary
Eliva believes that the outback is being invaded by aliens after hearing about "Alien species" at a gas station.

Main Cast

 * Lacey Chabert as Eliza Thornberry
 * Tom Kane as Darwin
 * Flea as Donnie
 * Danielle Harris as Debbie Thornberry
 * Tim Curry as Nigel Thornberry
 * Jodi Carlisle as Marianne Thornberry

Guest Stars

 * James Earl Jones as Alien Z: The main antagonist of the special. He is an genetically engineered gray alien that escaped from a Government Facility near Sydney, Australia. He questions the meaning of his life due to the circumstances of his birth and strikes back against humanity to prove his own worth. Possessing great psychic power, he is able to manipulate the weather, control the minds of others and verbally communicate telepathically.
 * Kevin Michael Richardson as Koba: A powerful yet very overconfident genetically engineered reptilian humanoid like alien (resembling a bodybuilder). He was rescued by Alien Z along with the other genetically engineered aliens and in return he greatfully serves as Alien Z's warrior. He is also shown to be a very skilled sword fighter.
 * Frank Welker as Babu: A dim-witted genetically engineered baboon like alien. He was rescued by Alien Z along with other genetically engineered aliens and in return he greatfully serves as Alien Z's sidekick. He is also Zini's sidekick.
 * John DiMaggio as Zini: An intelligent genetically engineered fox like goat like alien. He was rescued by Alien Z along with other genetically engineered aliens and in return he greatfully serves as Alien Z's sidekick. He is more intelligent of a dim-witted duo consisting him and Babu.
 * Mark Hamill as Stein: A shy genetically engineered tapir like alien. He was rescued by Alien Z along with other genetically engineered aliens and in return he greatfully serves as Alien Z's scientist.
 * Jeff Bennett as Jack Smith: A debonair and charismatic tourist guide and an old friend of Marianne Thornberry.
 * Jim Cummings as Ted: A koala who helps Eliza deal with the aliens.
 * Jim Cummings as Fang: A saltwater crocodile who helps Eliza deal with the aliens.
 * Adam Garcia as Roger: A red kangaroo that is going through a mid-life crisis after his only son Giam got eaten by Zander's pack, and has a great hatred for him. He helps Eliza deal with the aliens.
 * Isla Fisher as Nya: A wedge tailed eagle who is feircly protective of her young. She helps Eliza deal with the aliens.
 * Denis Leary as Zander: A dingo who's pack ate Roger's son Giam. He is unaware of Roger's hatred for him and thinks he is delurios. He helps Eliza deal with the aliens.
 * John DiMaggio, Kevin Michael Richardson, and Keith Ferguson as Harold, Frank, and Pete: A trio of razorbacks who help Eliza deal with the aliens.
 * Hugh Jackman as Horner: A water buffalo who helps Eliza deal with the aliens. Horner has seen the effects of other invasive species like him and thus battles the aliens with as much power as he can force.
 * Steve Carell as Slasher: An emu who helps Eliza deal with the aliens. He is also Horner's best friend.

Trivia

 * Alien Z's personality, character, and appearance is inspired by Mewtwo from Pokemon: The First Movie.