Building a trap.

My oldest son is currently working on a most interesting project. He is in the midst of designing a trap. This particular trap is not for an animal but is instead for something far more elusive. He has asked me to buy gold coins for his trap. The child insists that these are most necessary for this particular trap. The target of his trap is particularly drawn to gold and he is sure that having some in his trap will ensure his success. The child is trying to capture a leprechaun. I have no idea where he got the idea that leprechauns are something that can be trapped but it has filled his head. He is quite sure that if he succeeds in capturing a leprechaun that it will bestows riches upon us. While I would love a little extra pocket change I am trying to keep the child grounded. I applaud his creativity but I want him to realize he needs to work for the things he really wants as opposed to using tricks to get them.