When a certain episode of Pokemon contained contained a pattern of red and blue flashes capable of inducing epilepsy, 685 children were taken to hospitals, most of whom had seen the pattern not on the original Pokemon episode but on news reports showing the episode which had induced epilepsy.

At the very least, this needs a citation or two, since the following sources cast doubt on the story as presented:

WebMD's account

CNN's account

Snopes' account

And CSI's account, which includes the following:

At about 6:51, the flashing lights filled the screens. By 7:30, according to the Fire-Defense agency, 618 children had been taken to hospitals complaining of various symptoms.

News of the attacks shot through Japan, and it was the subject of media reports later that evening. During the coverage, several stations replayed the flashing sequence, whereupon even more children fell ill and sought medical attention. The number affected by this “second wave” is unknown.

And then goes on to argue that the large number of cases was due to mass hysteria.