Playing on sandbox 1-4 today everyone was encountering an invisible player - i told them all to reconnect (most of them did) and it was still happening. I walked around and found a player "steve the thief" floating naked above a spawn point, not moving, and invulnerable. I then proceeded to reconnect multiple times and each time he was still there. Either this is a player only (client side) bug or it is something which can be "turned on" at will. This player shows up in the player list. But never types. And when i tried to kick him, it says player not found.
This is currently proving a huge problem on the sandbox server.