I'm not the only one who has experienced this, a few others mentioned it too. During the Anniversary Bash, a small black dot appeared in front of my character, and stayed there for a while until the game was finished. Later on, the same thing happened, but the black dot had grown huge and was covering about half my screen.

In all my years of online playing, i've never seen such thing before. It's not really a big problem since i probably won't be seeing it again, but i've been wondering: do any of you have an idea what can have caused this? If it was lag, then it must have been a very weird kind of lag ;-P