Computer Soldier Porygon
Computer Soldier Porygon is best known as the "seizure episode" and has aired only once in Japan.
This episode is one of few that have made their way to being banned worldwide. One particular scene of this episode had a series of intense bright flashing lights, which caused approximately 700 Japanese children to be sent to the hospital with symptoms of epilepsy. The show went on hiatus for months and almost got cancelled as a result, but the episodes Holiday Hi-Jynx and Snow Way Out were delayed as a result. The episode also forced the producers to go back through the previous episodes and dim the lighting on them so as not to cause an accident of this magnitude again.
This episode is banned worldwide