Ditto's Mysterious Mansion (Pokémon The Series: Original Series)

Ditto's Mysterious Mansion (Japanese: メタモンとものまねむすめ Metamon and the Copycat Girl) is the 37th episode of the Pokémon anime. It was first broadcast in Japan on December 9, 1997, and in the United States on October 26, 1998.

Plot
Ash, Misty and Brock seek shelter in an old house and learn that it's no ordinary building; the gang is not alone in the house, as they meet Duplica and her mysterious Ditto.

Why It Rocks

 * 1) This is a fun filler episode that introduces the audience to a good character from the original series named Duplica, who is a pretty good imitator.
 * 2) The plot is well-done, telling the story of a Ditto who can transform, but its face always stays the same, with Duplica trying everything she can to help it imitate faces.
 * 3) The beginning is fun, as the gang goes into Duplica's "House of Imite" to take shelter from a sudden rainstorm, where they meet Duplica and the mysterious Ditto.
 * 4) The music is amazing, and fits really well with the episode.
 * 5) The quick battle Ash has with Duplica shows that Ditto is a tricky Pokémon to defeat, with Bulbasaur quickly getting stuck in Ditto's imitated Vine Whip, shocking Ash and the others.
 * 6) It was nice that Ash thought about what it means to be a Ditto trainer, and that it's pretty hard.
 * 7) Great animation for its time, especially for the Indigo League season.
 * 8) Many hilarious moments in the episode, such as:
 * 9) * Ditto's face staying the same on everything it transforms into until Team Rocket accidentally succeed in getting it to imitate faces perfectly.
 * 10) * Ditto transforming into a book when Jessie tells it to transform into a Dratini pictured in said book.
 * 11) * Duplica and the gang imitating Team Rocket, complete with a butchered version of their motto.
 * 12) * Team Rocket trying to dress Meowth up like a Dratini, only for them to argue and fight each other.
 * 13) Duplica's costumes all look really good on her, especially the Nurse Joy and Team Rocket ones.
 * 14) Team Rocket are funny as always in this episode, and they accidentally help Ditto imitate faces perfectly, much to Duplica's happiness and Jessie's frustration.
 * 15) When Team Rocket attempt to trick Duplica by giving her the real Meowth instead of Ditto, she immediately realizes this and throws Meowth back into Team Rocket's balloon as they try to fly away. Ditto then bites Jessie, forcing her to let go in pain as Ditto jumps out of the balloon and into Duplica's arms.
 * 16) Duplica's Ditto is impressive, as it shows off what other Dittos can do: transform into anything, not just other Pokémon. One of the best examples is when it transforms into a cannon so it can fire Pikachu straight at Team Rocket's balloon.
 * 17) Team Rocket suffer another hilarious defeat when Ditto transforms into a cannon and fires Pikachu at them, with Pikachu using his Thunder Shock attack to hit them, causing Meowth to accidentally claw their balloon and send them blasting off again.
 * 18) Heartwarming moments between Duplica and her Ditto.
 * 19) Great ending: Duplica reopens her House of Imite, ready to perform again with her Ditto, and the gang bids her farewell as they continue their journey.

The Only Bad Quality

 * 1) Brock commenting that Duplica's Nurse Joy and Officer Jenny disguises, while good, don't capture the adult charm of the real Joy and Jenny, is a pretty sour comment.

Reception
"Ditto's Mysterious Mansion" was met with positive reception by both fans and critics, gaining an 7.6/10 on IMDb.

Duplica and her Ditto proved to be popular enough that they returned in the Season 4/Johto League Champions episode "Imitation Confrontation", bringing along a second Ditto named "Mini-Dit".

Trivia

 * This is the first time that Ash and his friends mock Team Rocket's motto completely.
 * Duplica claims that Ditto is the only Pokémon that can use the "Transform" ability, even though Mew shares that ability. However, since Mew was supposed to be a secret Pokémon at this point and hadn't made its debut appearance in Pokémon: The First Movie yet, it's likely that Duplica doesn't know about Mew's existence.
 * It is revealed that Ditto can also transform into inanimate objects like books, photo-frames, cannons, etc.
 * It is also revealed that Ditto cannot transform into a Pokémon from a picture, as there must be a real one around for it to imitate.
 * Also, since it gains all the abilities of the Pokémon it transforms into, if that Pokémon has learned to speak human language, then Ditto can temporarily gain that ability for itself.
 * This was the last Pokémon episode to air in Japan before the "Electric Soldier Porygon" incident.