On Tuesday, December 16, 1997 at 6:51 PM, roughly 4.6 million Japanese households watching episode 38 of Pokemon, Dennou Senshi Porygon, saw Pikachu's thunderbolt trigger a red and blue strobe flickering at 12 hertz for four seconds. Within hours, 685 viewers had been taken to hospitals by ambulance, 208 required hospital care, and three arrived unconscious. This episode dissects the animation techniques called paka-paka and flash, the neurology of photic driving, and why alternating deep red and blue at that frequency overwhelmed the visual cortex.

We separate genuine photosensitive seizures from mass psychogenic illness, including an estimated 12,000 mild cases and a three-year follow-up showing most severely affected patients had never had a seizure before. We then follow the corporate fallout: TV Tokyo's apology and four-month hiatus, p ...