There was an episode of Pokemon aired in 1997 called "Denno Senshi Porygon." It wasn't released in America, and I'm about to explain why. At a certain point, flashing lights were shown, causing seizures, dizziness, and a number of other things. An apology video was aired, and things went back to normal. But that's not all.
Porygon AND its evolutions were BANNED from the anime FOREVER. Really? It's been 23 YEARS! Just don't put flashing lights in the episode! And what the heck did Porygon2 and Porygon-Z do? Spread the word. #saveporygon
And for the record, it was PIKACHU who caused the flashing lights, not PORYGON.