EP066

The Evolution Solution (Japanese: ヤドンがヤドランになるとき When Becomes ) is the 66th episode of the Pokémon anime. It was first broadcast in Japan on October 15, 1998 and in the United States on October 2, 1999.

Blurb
''Ash decides to join his mom and friends who are vacationing on Seafoam Island. While there, he searches out the programmer of the Pokedex to get information about the evolution of a Slowpoke. The mystery of how Slowpoke evolves into a Slowbro is surprisingly revealed when Team Rocket makes their usual bumbling interference.''

Plot
is surprised to learn that his mother, some of Pallet Town's locals, and are going to go to the Seafoam Islands for a beachside holiday. Delia tells Ash that he has to stay behind to train, just as the tour group leaves shortly after. Ash goes to 's lab, only to discover that Oak is trying to find out why evolves into. When Ash suggests that he use the Pokedex to search for answers, Oak is instantly reminded of Professor Westwood V, a Pokéologist and the original creator of the Pokédex who would know the answer. He conveniently lives of the Seafoam Islands, so Ash and quickly decide to assist, capitalizing on an excuse to go to the beach.

Ash arrives and surprises and. They walk to Westwood's lab, where they discover that he is actually the fifth of many Westwoods, and insists on being called that. He is also trying to figure out the mystery of Slowpoke and, and hopes to present a theory to the world's leading body of Pokéologists, the Pokémon Suppositum. Westwood V goes outside to fish, trying to understand Slowpoke. As Ash and his friends find a Slowpoke sitting next to them, comes out of its  and talks to the Slowpoke. After what seems to be some random, unintelligent conversation, a comes out the water. It first grabs onto Slowpoke's tail, and then Psyduck's, inflicting great pain. The team decides to go have some lunch for a break.

Meanwhile, is taking a vacation on the beach and making Jessie and James dig for clams, having already cleaned his private yacht. Upset that they cannot take a break, James digs up a Shellder and decides to try to capture it. James calls out and defeats the Shellder with, but Jessie steps up to capture it, much to James' disappointment. They go to the Boss, but he disapproves of their capture and orders them to steal potentially invaluable information from Westwood V's lab.

Westwood V shows Ash and his friends a computer simulation of Slowpoke's evolution, and notes the form change Shellder undergoes when it clamps on to Slowpoke's tail. arrives in a parasail and startles everyone when it crash-lands on the lab's balcony. After performing their, they hand Westwood V a paper with their own "Team Rockédex" entries about themselves. Westwood V is instantly impressed by 's speech and starts writing notes. He then realizes that Team Rocket may be trying to enslave him and tries to escape. The trio finds that the only Pokémon Westwood V has is a Slowpoke.

Westwood V tries to flee with his Slowpoke, but after tripping, Team Rocket catches up and sends out Shellder to make it evolve into Slowbro. To everyone's surprise, Slowpoke, regarded as the Dopey Pokémon, runs around in an attempt to flee from Shellder. Misty decides to intervene with the seaside location perfect for her Pokémon, but Psyduck emerges. Psyduck turns around and Shellder onto its tail instead. After a delayed pain reaction, Psyduck throws Shellder off, sending the Pokémon flying. Weezing attempts to knock Psyduck out, but only bounces on its head. Infuriated, Jessie throws Shellder again, but it clamps onto Psyduck's head this time, giving it a major headache. Psyduck, now much more powerful because of its headache, uses to stop everyone and its  sends Team Rocket flying. It suddenly loses concentration, however, both Team Rocket and Shellder land close by. As Slowpoke walks towards Psyduck to thank it, it trips and Shellder clamps onto its tail, evolving it. Team Rocket runs back to grab Slowbro, but it uses, causing Team Rocket to blast off again.

Misty asks if Westwood V figured out why Slowpoke evolves. He answers confidently, with a brand-new theory, that. He explains that Shellder helps Slowpoke to balance on two legs instead of four, freeing its hands so it can use Mega Punch, and Shellder gains land transportation on Slowpoke's tail. As the group leaves, Ash thinks Psyduck may want to say goodbye to Slowbro. Misty, Ash, and Brock watch on as the two Pokémon have a rather slow conversation.

Major events

 * Jessie catches a that James wanted to catch, but it attaches itself to Professor Westwood V's, catalyzing its evolution into a  and thus leaving her.

Humans

 * Jessie
 * James
 * Delia Ketchum
 * Professor Westwood V
 * Professor Westwood I, II, III, and IV (portraits only)
 * Delia Ketchum
 * Professor Westwood V
 * Professor Westwood I, II, III, and IV (portraits only)
 * Professor Westwood V
 * Professor Westwood I, II, III, and IV (portraits only)

Pokémon
Who's That Pokémon?: (US and international),  (Japan)
 * (Jessie's; new; evolves with Slowpoke; leaves)
 * ('s; Mimey)
 * (Professor Westwood V's; evolves)
 * (Professor Westwood V's; newly evolved)
 * (Jessie's; new; evolves with Slowpoke; leaves)
 * ('s; Mimey)
 * (Professor Westwood V's; evolves)
 * (Professor Westwood V's; newly evolved)
 * (Professor Westwood V's; evolves)
 * (Professor Westwood V's; newly evolved)

Trivia

 * Professor Oak's Pokémon Lecture:
 * Pokémon senryū summary: "I want to see an using a fork."
 * Part of the lecture for this episode was used in the dub as part of the introduction to the VHS version of Mewtwo Strikes Back.
 * The book Prepare for Trouble is partially based on this episode.
 * imitates of  after  appears and sticks out its tongue by saying "Oh, you're a wise guy, huh?"
 * Music from Mewtwo Strikes Back and Pikachu's Vacation is played in the episode. However, the background music is replaced in the dub.
 * The title is a reference to  (Swedish translation: Om arternas uppkomst).

Errors

 * says that used its "tail wag attack", although in multiple episodes, she says the proper name "".
 * When uses,  and  are stunned, and  says, "That's supposed to make its opponents forget!" This is untrue, since Amnesia only affects the user in the.

Dub edits

 * Pikachu's Jukebox: My Best Friends
 * The setting of the episode is said to be the Seafoam Islands (referred to here as a singular "Seafoam Island") in the dub when, in actuality, it is an -exclusive location called Binnes (ビンヌ; a reference to ) in the Japanese version, which has no relation to the aforementioned game location.
 * Professor Westwood V is outright said to have programmed the Pokédex in the dub, when he was simply one of the people to write the device's bestiary in the Japanese version.
 * James tells to use  in the dub. In the original, it was told to counterattack.

In other languages
Rätselhafte Entwicklung EP068 EP066 EP066 無印編第66話 精灵宝可梦 第67集