History
Hagg was an alien who collected creatures from all over the universe for his private collection as trophies. He eventually came to earth to collect humans and abducted Bret Marlowe, a big game hunter to inform humanity of his purpose, believing that if his game knew that he was coming, it would make the capture more exciting and released him.
However no one believed Marlowe until it was too late and Hagg proceeded to capture Americans and then the Soviets. Unfortunately his superior technology enabled him to ignore humanity’s best efforts to destroy him until Marlowe tricked him, luring him into an ambush and having a gigantic steel net dropped on him, forcing Hagg to surrender.
An honorable alien, Hagg voluntarily released his captives and due to intergalactic law, left Earth and has not been seen since.