This is a trap made almost specifically for Co-op, or against bots. It works ridiculously well. Rules for using it: If you are being chased, jump OVER don't walk through. If builders are stuck inside, you move forward (but do not OPEN the trap), and then you move back. Moving back sort of 'drags' the bots towards you, they think you are running away and chase you. If you stand still they will get anxious and start to break the trap. If you stand on TOP of the trap they will aim to get UP to you. do not. You stand to the left of the trap, and never go above it, ever while it is occupied. Any 'materials' the people drop end up on top where you can safely grab it. When everyone is gone from the trap you can collect the coins. I have many modifications of this for hills and such but it works best on straight flat land.