[gwillen]

I got something like that not long ago, and it was diagnosed as acute macular neuroretinopathy. Luckily, in many cases it apparently resolves on its own, and mine did. Was the spot slightly off-center in your vision? That's where it tends to happen.

As I recall, it's fairly random and fairly rare, but apparently it's been seen a bit more during COVID.

[totetsu]

Mine is a cone shape extending out from my natural blind spot with the point ending just before the center of vision. so It's easy to miss with both eyes open. If I close one eye and look at a word, the word a few words to the right is.. a strange blur of the colours around it.