Cracked by Navin, Bad Ass Thambi, Vivek, lordmaldy, Karthik and me!!
Answer : The episode Dennō Senshi Porygon ("Electric Soldier Porygon") is infamous for using visual effects that caused seizures in a number of Japanese viewers, an incident referred to as the "Pokémon Shock" by the Japanese press. Six hundred and 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.