The Iron Giant (1999)

In 1957, a large alien robot crashes from orbit near the coast of Rockwell, Maine. After being rescued by a young boy named Hogarth, the Iron Giant follows him back to his house and befriends him. However, a paranoid government agent named Kent Mansley discovers evidence of the Giant and tries to track him down. Hogarth and the Giant seek help from beatnik artist Dean McCoppin and try to evade Mansley. Eventually, they are discovered by the military and attacked, leading to a climax where the Giant sacrifices himself to save the town of Rockwell.