Between August and November 1977, the island municipality of Colares in the Marajó archipelago of Pará, northern Brazil experienced one of the most intense sustained UFO flaps ever officially investigated by a national military force. Residents of the fishing villages of Vila de Colares, Caratateua, and Mosqueiro reported nightly incursions of luminous objects emerging from the Amazon mouth and projecting intense directed beams of light at sleeping people. More than eighty individuals were injured, several with visible radiation-like burns and blood-loss marks, and at least two elderly women were reported by the Colares hospital to have died from the attacks.
The phenomenon was popularly named 'Chupa-chupa' ('vampire-suckers') for its persistent feeding-like behaviour: witnesses reported being paralyzed in their beds, seeing a vertical beam of red or green light pass through their roof, and awakening with small puncture wounds and significant anaemia. The Brazilian Air Force's First Regional Air Command (I COMAR) launched Operação Prato ('Operation Saucer') under the field command of Captain Uyrangê Hollanda on September 19, 1977, stationing an investigation team at Colares for four months. Hollanda and his men documented more than 500 individual encounters, photographed multiple objects in daylight, and recovered physical evidence including radiation readings, melted electrical cables, and soil-contamination samples.
The Operation Prato files were declassified in 2005 under Brazil's transparency laws, producing some of the most substantial government-generated UFO documentation in history — 500+ pages of photographs, reports, witness testimony, and commander's logs. Captain Hollanda, in interviews before his 1997 death by suicide, stated that he had personally witnessed multiple objects, that the phenomena were real, and that the Brazilian military had decided not to engage further. Brazilian UFO researcher Ademar José Gevaerd, editor of Revista UFO, has described Colares as 'the most significant case in world UFO history.' The phenomenon abruptly ceased in November 1977 and has not recurred at the same intensity.