As you can tell from the video we thought it was hackers, and that they were trying lag out the server, which sorta worked if they were since I had about 3 fps You are recording a game(fraps i guess?), see a "bunch" of mobs, and because you have 3 fps you think there are hackers to "overload the server". fps droprate isn't caused by the server, but your computer not able to handle the framework. Was probably just an admin having fun, or you extreamly lucky to see a spawnbug in the mod. But props to your guess about the hackers dude (Y)