If you look BEHIND, and rapidly hit a trading villager and move left-right, you'll see a player with random armor who is not shown on player list behind you.
It's probably a staff checking if you're hacking or not. Also if you continue doing that when he is there, you'll get kicked for "CLIENT-MODIFICATION". If you stop, he'll just disappear.
It's probably a staff checking if you're hacking or not. Also if you continue doing that when he is there, you'll get kicked for "CLIENT-MODIFICATION". If you stop, he'll just disappear.