Brainiac is a bald, green-skinned humanoid who arrives on Earth and shrinks various cities, including Metropolis, storing them in bottles with the intent of using them to restore the then-unnamed planet he ruled. He was originally notable only for having shrunk the bottle city of Kandor with his shrinking ray and for using a force field. In his initial story, he also traveled with a white alien monkey named Koko; the monkey also appears in a 1960 "Superman" story retelling the story of Kandor's disappearance ("Superman" #141 (November 1960)). Koko was quickly dropped from Brainiac's stories, but a version of the monkey has made sporadic appearances as the villain's pet in the series "Justice" and the 2008 storyline "Brainiac" in "Action Comics". The villain's descendant Brainiac 5 also had a pet named Koko for several stories in the 1990s.