One of Aesop's Fables also known as The Honest Woodcutter. In it, a workman dropped his axe into the river (or a lake or pond depending on the variations). The god Hermes found out what was wrong, and offered his aid. First Hermes pulled out a silver axe, and asked whether it was the one the workman lost. He told the god that no, it wasn't. Then Hermes pulled out a golden axe, and asked whether it was his. Again, the workman said no. Finally, Hermes pulled out the original axe, and asked if it was his. The workman said that yes it was his. As a reward for his honesty, Hermes gave him all three axes.
Another workman, hearing of this, purposefully drops his axe into the river. He claims it was the golden axe, and ends up not getting any of them, not even his original axe.
This story appears to have become a common part of Japanese culture, with Mercury replaced by a "water sprite" or some such. It is often parodied, including in an episode of Doraemon featuring a gadget called the "Woodcutter's Pond" which functions similarly to the fable.
