@Maenad Mmm, my migraine aura usually manifests more as either slight tunnel vision and/or photosensitivity? But yeah, migraine is one possible suspect.

So far I'm thinking it was just some random cluster of neurons in my visual cortex getting excited for no obvious reason. (I guess you could call that a micro seizure.)

AFAIK I'm not prone to those, though. Then again, my neurology has baffled scientists for about 40 years. 🙃