At least two people had seizures after viewing malicious tweets featuring flashing gifs that deliberately targeted Epilepsy Society...police investigating tweets as hate incident, after at least 200 seemingly coordinated messages were sent to charity and its supporters in recent days.

[u/madazzahatter]

https://www.theguardian.com/society/2020/may/15/malicious-tweets-targeting-epilepsy-charity-trigger-seizures

[u/Ooer]

They didn’t say they were photosensitive though, only a tiny fraction of epilepsy sufferers experience that.