When someone shits in a box and then wraps it up and gives it to someone as a present. The reciever of the present will be unaware that in the gift wrapped box is a big turd, until they unwrap it and the smell hits them.
Little Billy awoke on christmas morning and ran down stairs in glee. He looked under the tree to find a huge mountain of presents. He picked up the biggest one and started tearing off the paper in excitment. He opned the box and inside was a stale old heap of human feces. Billy's father stood and laughed while his son cried at the horrific gift. "Hope you liked my lucky santa, son." exclaimed billys father.