The Ipupiara, Igupupa or Hypupiara (from the Tupi ïpupi'ara, "marine monster"), according to the Tupi of the present Brazilian coast in the 16th century, was a sea monster and cannibal.A chronicle by Pero de Magalhães Gândavo, published in 1575, tells that an ipupiara appeared in 1564 on the beach of São Vicente (SP), the first Brazilian village, and terrified the Indian slave girl Irecê, who was going to find her lover on the beach and saw the Appearance of the monster as a punishment. The ipupiara, apparently, had already killed his lover, Andirá. She fled in terror, but on the way she found Captain Baltasar Ferreira, who confronted the monster and struck him down with his sword. (It was the representative in São Vicente of Captain Pedro Morras Ferreira Barreto, who resided in Santos.) According to the chronicler, the monster had "Fifteen spans long" (3,30 meters) and was "sown with hair by the body and on the muzzle had silks as big as mustaches". Another colonial chronicler, the Jesuit Fernão Cardim, said that such creatures were of good stature, but they were very repulsive. They killed people by hugging them, kissing them and squeezing them until they suffocated. These monsters also devoured human eyes, noses, the tips of the feet and hands, and the genitals. They also existed in the feminine form, having long hair and very beautiful. The Ipupiara was, according to these chroniclers, a being "bestial, hungry, disgusting, primitive and brutal ferocity."Jean de Léry, in his work Viaje a Terra do Brasil, tells something similar, which he heard directly from the Tupinambás Indians of Guanabara in the 16th century: (...) I do not want to omit the narration I heard from one of them of a fishing episode. He told me that, once with others in one of his wooden canoes, for a quiet time on the high seas, a great fish appeared, holding the vessel with its claws, seeking to turn it or to enter it. Seeing this, the savage went on, I sliced his hand with a scythe and his hand fell into the boat, and we saw that he had five fingers like a man's. And the monster, aroused by pain, put his head out of the water, and the head, which was human in form, let out a small groan. (...)It is probable that the ipupiara of Baltasar Ferreira was a sea lion, an animal little known and frightening for the Indians of the paulista coast, because rarely appears in such latitudes.
Later, this being was confused with the boiúna or great snake of the Amazonian legends, a giant, voracious black sucuri that could also take the form of a boat. Also known, from the eighteenth century, as a mother of water, she came to be also imagined as a woman.
It was only in the 19th century that the deceptively indigenous name of Uiaraou iara appeared, romantically imagined as a tropical and Indian version of the janas, nixes and loreleis of European folklore, dragging the unwary to death in the streams with their beauty or their song.