Regarding the 1977 Colares, Brazil UFO flap (which involved “aggressive” UFOs… a Brazilian General who was involved in the events: “Those NHIs behind the [UFO] craft were not being aggressive but rather were developing a vaccine that would protect them from any disease to which they might be at risk by collecting fluid and tissue samples from humans.” Assimilation is the name of the Grey Game… Info from Caplan’s Not For Disclosure