There will be a small shack and it has a sign that says Free Diamonds! and when they get in the will be in adventure mode and when they open the trapped chest to get the diamonds the chest will be connected to dispensers that will blast arrows and lava and also there will be a command block that will be saying a taunt like HAHA or You've Been Pranked! and then your victim will go back to the minecraft world in heaven.

Additional Notes

NOTE: The tutorial of this contraption will be in this youtube account:http://www.youtube.com/user/TheRRCrafters