"Chupas are mysterious objects, or UFOs, allegedly seen by night in the eastern forests of (mainly) Brazil. They are described as smaller, metallic-like objects that fly about the treetops, making a humming sound like a refrigerator or a transformer. Since most people in the area are poor, they often go out during the night to hunt food, such as deer. To do this, they climb up in trees to await their prey. It is often during this period of waiting that hunters claim to spot the chupas. When seen, chupas are claimed to emit a bright white light. Instead of being “just unidentified objects” or lights, they are alleged to be lethal. In some cases, people claim to have been hunted by them. It is claimed that this often results in all kinds of pain for days (sometimes years) after their experience. It has also been claimed that some people have even died from the alleged lethal beams emitted by the chupas, and that some hunters have tried to shoot at the chupas, with no effect."
Sounds like Predators to me.