The Toad and the Firefly.
A fat toad wallowed in mud one crisp summer night when it noticed the glow of a firefly flitting overhead. Like a bolt of lightning the toad's sticky tongue leapt from its mouth to ensnare the glowing fly.
But before the toad could make its meal, the firefly cried out, “Wait oh winsome toad, master of life and death! If you spare my life, I will grant you a wish, so long as your wish is in principle possible.”
The toad guffawed, “I will not fall for such clumsy a ruse! You ought instead to have told me you were poisonous. With your current story, even if you were telling the truth I would only hunt you night after night, looking for wishes granted. But you can grant one wish... I wish for a fine supper.”
And with that the firefly was gobbled up.