In one of Aesop's Fables, a workman dropped his axe into the river. The god Mercury found out what was wrong, and offered his aid. First Mercury 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 Mercury pulled out a golden axe, and asked whether it was his. Again, the workman said no. Finally, Mercury 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, Mercury 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.
Parodies thereof abound after a episode of Doraemon featured the "Honest Axeman's well", which a user can drop anything into the well and the "water sprite robot" will came out with the same kind, but better item to what user dropped. The rest is worked like original fable.