Playing Hearthstone ranked mode, I was matched up against someone with the username "Your Opponent". This was odd for several reasons:
Normally, the opponent's rank is shown on the initial screen, but this time the opponent's rank wasn't listed.
I thought you couldn't get spaces in a Blizzard BattleTag (except through RealID, but presumably their real name as shown on their driver's license isn't actually "Your Opponent").
After the match, when I went to friends list and looked at the username of the player I last played, it didn't show "Your Opponent" under "Last Played:"; it showed some username (but the username was greyed out, instead of shown in blue as it usually is).
So what is this indicating? Can one actually set their BattleTag to be "Your Opponent", or is this the game's way of indicating something about that player?
I tried searching, but as you can imagine, a search for "Hearthstone Your Opponent" turns up a lot of unrelated information. I did find a few other people who reported seeing something similar (1, 2) but didn't find an explanation.