Men in Black - Mikey - First Alien

Men in Black is an American science fiction action comedy film directed by Barry Sonnenfeld from 1997. The film presents the fate of agents of secret institution who monitor and police extraterrestrials who live in secret on Earth. 

In the first scene MiB Agents K and D interrupt a border patrol sting at the Mexico–United States border to apprehend Mikey, a disguised extraterrestrial - a creature that was concealed by a human camouflage.