Boiuna

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Boiuna, meaning “Black Snake,” is a legendary creature in Brazilian folklore. It is also called Cobra-Grande (“Large Serpent”) and Mboiaçu. The Boiuna is a nocturnal, black river serpent and the most powerful creature in the rivers of the Amazon rainforest. It can change shape to scare away fishermen who enter its territory, appearing as a canoe, a sailboat, or even a woman.