I came across a new phenomenon when I was playing HL2DM (that was a
map called "steamlab"). There was a guy who was obviously psiised off
that I killed him often. He went into the "spectate" mode for a
fraction of second, and then back into the game. After that, I stuck
were I was. If I pointed the crosshair of my weapon at floor, the name
of that player came up in yellow letters as if I was aiming at him. I
shoot my weapon, and I saw the splashes of blood. But I could not kill
him or whatever it was. Then, usually somebody came and killed me.

This happened several times. I suspect this could be a new exploit.
Has this happened to anybody else ? What was that ?