Yacumama

Yacumama, is a mythical enormous serpent believed to inhabit the Amazon Rainforest. According to legend, it is considered the mother of all aquatic animals and would suck up any living thing that passed within 100 steps of it. To protect themselves, local Indigenous peoples would blow on a conch horn before entering the water, believing that the Yacumama would reveal itself if it were present. (Wikipedia)