I dare say I'm going to win this one.... It was around 3 weeks ago and I'm still mega salty.
We got a wild Unown in a nearby village, the first one ever seen in our town and only the 2nd in our whole county (there have been no further reported sightings since)
I got the shout from our local spots chat... Got there as fast I could... Was there with approx. 3 minutes left before it despawned... My mobile provider was having problems with their mobile data and I couldn't get on the game
Worst bit... Someone I know quite well from playing the game was on the opposite street (it was between a row of houses accessible from 2 roads) and caught it... She'd have happily given me a tether if she had seen me