I'm on a large university IP address - it's possible that someone else was doing this too under the same IP*

It was a $10 bet on Gems & Stones (Endorphina) that netted 3.2BTC.

I have a screenshot but I can't upload it here for some reason, but I'm not lying (there's no reason to).

*My roommate and I were actually playing off the same computer. So in fact, I do know that we were at different times on the same computer that manages our R4 cloud.
** No bonus wager requirements were active or used