This is an Aesop's fable, though its origin may be even older. A mountain began groaning loudly one morning. All the nearby people stopped work and went to see what was happening. They all speculated on what was causing the noise – could it be an earthquake? or was there a giant trapped inside?

As the groaning grew louder and louder, everybody came to believe that the mountain was in labour. People came from far and wide, waiting to see what monster it would give birth to. At last the mountain let out a tremendous noise, and then a huge crack appeared all down its side. As the crowd waited, they saw something moving inside…and finally a mouse came out, saw the people and ran away into the long grass.

The message seems to be that result isn't always in proportion to effort; or that those who make the most noise don't produce the most impressive results.