"Dennō Senshi Porygon" (でんのうせんしポリゴン Dennō Senshi Porigon, literally "Computer Soldier Porygon", although most commonly translated as "Electric Soldier Porygon") is the thirty-eighth episode of the Pokémon anime's first season. It was first broadcast in Japan on December 16, 1997, and has since not aired anywhere else. In the episode, Ash and his friends find at the local Pokémon Center that there is something wrong with the Poké Ball transmitting device. To find out what's wrong, they must go inside the machine.
The episode is infamous for using visual effects that caused seizures in a number of Japanese viewers, an incident referred to as the "Pokémon Shock" (ポケモンショック ,Pokémon Shokku?) by the Japanese press. Six hundred eighty-five viewers were taken to hospitals, but only two people remained hospitalized for more than two weeks. Due to this, the episode has been banned worldwide.
After the shock, the Pokémon anime went into a four month hiatus, and it returned on TV Tokyo in April 1998. Since then, the episode has been parodied and referenced in cultural media, including an episode of The Simpsons where the Simpsons go on vacation to Japan and watch a cartoon called Battling Seizure Robots, resulting in the entire family going into convulsions. In a South Park episode, Kenny McCormick suffers from a seizure after playing a videogame called "Chinpokomon". Because of this Porygon2 and Porygon-Z have never appeared in the anime by a bad flash. This is in the Guiness World Records in the Most seizures caused by a TV program. This is a big history to Pokémon anime If you watch this online it will have a warning sign. Also see Pokémon-Regarding Porygon
Ash, Misty, Brock hurry to a Pokemon Center to heal Pikachu, who is worn out. When they get to the center, Nurse Joy is very frustrated because the Poké Ball Transporter isn't working. Everytime she sends a Pokémon to another center, the Pokémon never arrives and its replaced by another Pokémon.
Dr. Akihabara, the inventor of the Pokémon Transport System, is at the center trying to figure out what went wrong. Brock says a virus may have gotten into the system, but Dr. Akihabara says that that's not possible because he designed the circuits so well. Ash, who is a bit confused, says that the computer could be sick. Nurse Joy has heard of an Anti Virus Vaccine, a powerful device that fixes the problem. But, when Dr. Akihabara looks further into the system, he gasps and then quickly leaves the center.
Ash and his friends go to Dr. Akihabara's huge manison to find out what happened to him. Inside, the doctor leads them into a room with a giant machine in it. Dr. Akihabara orders them to enter the machine and when Ash and his friends do, Dr.Akihabara tells them they have entered the Human Transporter only after he has locked the door.A Porygon appears before Ash and his friends and the doctor introduces them to Porygon. He explains that Team Rocket has stolen his other Porygon and are blocking the Poké Ball Transporter, keeping all of the Pokémon for themselves. Dr.Akihabara can't send in the Anti Virus Vaccine because there are people inside the machine. He asks Ash and his friends to go into the transporter and get Team Rocket out. They refuse but Dr. Akihabara sucks Ash, his friends, and Porygon into cyberspace anyway.
Ash and his friends fall into cyberspace, but Porygon grows in size, flies over, and catches them. Riding on Porygon, they fly over to Team Rocket.
Team Rocket is celebrating over what they have done, claiming they have gone where no human has before. Just as they say no one will catch them, Porygon flies over and Team Rocket challenges them to a battle. Jessie and James send out Arbok and Weezing. Weezing uses Poison Gas on Porygon, making Ash and his friends cough. Porygon uses Conversion and its skin turns purple. Porygon charges, with Ash and his friends still riding it, at Arbok and Weezing, knocking them out of the battle.
Team Rocket sends out their Porygon, which looks lke Dr. Akihabara's Porygon except it has a flag with an R on its tail and a 0 on its forehead. Team Rocket's Porygon uses Sharpen to gives itself a swordlike beak and it tries to attack Dr. Akihabara's Porygon. Ash and his friends use the barrier Team Rocket made to hold back all of the Poké Balls from the Pokémon Centers to attack Team Rocket. Porygon sends Team Rocket and their Porygon blasting off again.
Then, a T.V. appears and Dr.Akihabara's picture appears on it. He says that Nurse Joy hired another technician to put the Anti Virus Program in the computer. In his hurry, Dr. Akihabara forgot to tell Nurse Joy that there are people inside the computer. As the vaccine tries to hurt Ash and his friends, Porygon gets them on its back and tries to fly into the air to escape. From the ground, Team Rocket yells at Ash for running away from the battle. Ash tells them to run away from the vaccine. The vaccine destroys the rest of the Poké Ball barrier in flashing blue and red explosions. Meowth and their Porygon rescue Jessie and James from the sea of Poké Balls and they join Dr. Akihabara's Porygon to escape.
The vaccine transforms into a spaceship and chases after them. Inside the Pokémon Center, Nurse Joy and the technician are surprised by the resistance of the "virus" and they commannd the vaccine to use a powerful attack. The virus locks onto Team Rocket's Porygon, fires a laser beam at them, and sends Team Rocket into a cyberspace hole the vaccine made. Ash and his friends cover their eyes from the blinding red and blue light. The cyberspace bug holes cause a system error and Nurse Joy tells the technician not to use the attack again.
Team Rocket, lying at the bottom of a bug hole, realize that their Porygon is knocked out and they can't escape. Just as the vaccine is a bout to fire a laser beam at Team Rocket,Bulbasaur saves them. The weight of Team Rocket slows down Porygon as they head to the exit hole. The vaccine fires missles at Porygon and Porygon is so tired that it can't defend itself. Pikachu uses a huge electric attack that destroys the missles in a red and blue explosion that covers the entire television screen. (This is the part that caused the seizures) Porygon has enough time to reach the exit hole just before the vaccine fires more missles, destroying Dr. Akihabara's manison.
Ash and his friends are happy to be back in the real world. Team Rocket thanks them and when they leave, they forget about their Porygon. Ash and his friends go back to the center to see if the system is working again. It is and Nurse Joy is very happy, unaware Ash and his friends risked their lives to fix it. Ash decides it would be best not to tell Nurse Joy that they were in the system.
- According to Maddie Blaustein, 4Kids did dub this episode and reduced the speed and intensity of the strobe light effects. Although it is enough to make it safe to watch, they can't air it because of the worldwide ban on the episode.
See this link for other banned episodes.