The Chitauri (tʃɪˈtaʊri) are a fictional race of extraterrestrial shapeshifters appearing in American comic books published by Marvel Comics, specifically in Ultimate Marvel. They were created by Mark Millar and Bryan Hitch for the Ultimate universe franchise in place of the existing Marvel Comics alien species, the Skrulls, which play a similar role in the franchise's mainstream continuity. Marvel later chose to distinguish between the Skrulls and Chitauri of the Ultimate universe. The race first appeared in Ultimates #8 (Nov 2002), and later had counterparts on Earth-616. The species was also adapted to other media, most notably for films set in the Marvel Cinematic Universe. The race called Chitauri appeared as Ultimate Marvel's (Earth-1610) counterpart to the Skrulls. They are a shapeshifting alien species who have attempted to conquer the Earth, most notably during World War II and again in the early 21st century. The Chitauri claim to be part of "the immune system of the Universe", wiping out disorder and free will wherever they find it. They seem to prefer to act behind the scenes, mimicking and influencing the social and military methods of the species they are currently infiltrating. For example, they aided the Nazis in their attempt at world conquest by providing them with the technology to create a nuclear bomb carried by an intercontinental ballistic missile. However, this attempt was thwarted by the prototype super-soldier codenamed Captain America. Through the entire conflict of World War II, the Chitauri were being driven out of their operations in Africa and Europe, even from their main Japanese training camps in Hiroshima and Nagasaki. Following the end of the war, the Chitauri withdrew to make new plans. The next attempt at conquest was more subtle (at first), involving long-term methods of manipulation such as will-inhibiting drugs in many nations' water supplies, influencing the media, and R.F.I.D. (radio-frequency identification) microchips to be implanted in schoolchildren, among other means.