Koko was a small, white alien monkey that lived aboard Brainiac's star ship. Brainiac kept Koko as a pet and frequently brought him along on many of his conquests. Koko provided an attentive ear when Brainiac felt the need to engage in long-winded soliloquies.
Although he is only an animal, Koko has demonstrated surprising feats of intelligence and can apparently understand everything that Brainiac says to him.
- This version of Koko, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- On the DVD documentary, An Evening With Kevin Smith, movie director Kevin Smith regales the audience with an anecdote concerning an early script draft of the 2006 motion picture, Superman Returns. Warner Brothers executive producer, Jon Peters, approached Smith with an offer to write the film's screenplay and the two collaborated on ideas during several interview sessions. In the original treatment, Brainiac was to play an important role in the Man of Steel's triumphant return to the big screen. According to Smith, Peters suggested that Brainiac should have a humorous, prankish pet monkey as a sidekick. Whether Peters was aware of the existence of Koko or not is unknown. These early drafts were ultimately rejected and are not included in the final shooting script. To the dismay of many Koko fans, Brainiac's space monkey does not appear in Superman Returns.
- 10 Appearances of Koko (Earth-One)
- 1 Images featuring Koko (Earth-One)
- Quotations by or about Koko (Earth-One)
- Character Gallery: Koko (Earth-One)