The Space Phantoms are the servants of Immortus: Master of Time. For many years it was assumed that there was only one Space Phantom, but in the course of the Destiny War the Avengers discovered that there was more than one. During a journey back in time to 1873, a trio of Space Phantoms was caught impersonating the Gunhawks and the Black Rider.
The Space Phantoms were previously said to have originated on the planet Phantus, in the Phalbo system. Immortus traps individuals who become lost in Limbo, and due to the nature of that plane, they begin to forget their former lives and change into misshapen beings. Immortus conditions these into servants who can perpetuate his schemes and manipulations of historical events. The Phantoms can assimilate anyone, even to the point of torture and escaping notice of even mind-readers.
The first Space Phantom first appeared in Avengers #2 (September 3, 1963), copying Giant-Man, Iron Man, and Hulk. During his battle with the Avengers, he first copied the Hulk, and battled Iron Man. He took the shape of a flying insect to escape, but Iron Man continued to battle the Hulk. The Space Phantom attacked the Wasp in his insect form, and then became Giant-Man. After fighting Iron Man he took Iron Man’s form. He finally attempted to copy Thor and was banished back to Limbo because his powers couldn’t affect Asgardians. The Space Phantom was the cause of misunderstandings between the other Avengers and Hulk which led Hulk to quit the team.