"The Moon is made of green cheese" is a statement referring to a fanciful belief that the Moon is composed of cheese. In its original formulation as a proverb and metaphor for credulity with roots in fable, this refers to the perception of a simpleton who sees a reflection of the Moon in water and mistakes it for a round cheese wheel. It is widespread as a folkloric motif among many of the world's cultures, and the notion has also found its way into children's folklore and modern popular culture.