Dennō Senshi Porygon

"Dennō Senshi Porygon" (Japanese: でんのうせんしポリゴン, Hepburn: Dennō Senshi Porigon; translated as "Computer Warrior Porygon", although more commonly "Electric Soldier Porygon") (IPA: [deɴnoː seɴɕi poɾiɡoɴ]) is the 38th episode of the Pokémon anime's first season. During its sole broadcast in Japan on December 16, 1997, a scene with flashing lights induced photosensitive epileptic seizures in children across the country. Over 600 children were taken to hospitals. The incident is referred to in Japan as the "Pokémon Shock" (ポケモンショック, Pokemon Shokku).

The episode was written by Junki Takegami and directed by Kiyotaka Itani, and was broadcast on TV Tokyo. In the episode, Ash and his friends find that there is something wrong with the Poké Ball transmitting device at the local Pokémon Center. To find out what is wrong, they must go inside the machine. Towards the end of the episode, Pikachu stops a wave of missiles with an attack, resulting in an explosion that is depicted by rapid flashing lights that fill the screen.

After the incident, the Pokémon anime went into a four-month hiatus. The episode was pulled from rotation and was never aired in any other country. The incident complicated plans for an American localization of the series, and resulted in new broadcasting standards in Japan to ensure future incidents would be avoided.