Flex Mentallo is a fictional character appearing in American comic books published by DC Comics. Created by writer Grant Morrison and artist Richard Case in 1990, during their run on Doom Patrol. Flex is in part a parody of Charles Atlas' long-running "The Insult that made a Man out of Mac" advertisements seen in American comics from the past. In 1996, Flex Mentallo appeared in a self-titled, four-issue miniseries written by Morrison and illustrated by Frank Quitely. The miniseries forms part of what Morrison calls a thematic hypersigil trilogy along with The Invisibles and The Filth. Mentallo appears in his first live-action adaptation on the Doom Patrol television series for DC Universe and HBO Max, portrayed by Devan Chandler Long. Publication history Flex Mentallo first appeared in 1991 in issue #35 of Grant Morrison's run on Doom Patrol as a member of the audience for Danny the Street's Perpetual Cabaret. Later in the storyline, Flex reveals that he is actually "The Man of Muscle Mystery", and tidies his appearance. In issue #42, Flex is revealed to be not an entirely original creation, but rather a parody of the post-workout protagonist of Charles Atlas' long-running "The Insult that made a Man out of Mac" advertisements seen in American comics from the past. Also parodied was My Greatest Adventure, the title in which the Doom Patrol originally appeared. Part of a long string of fictional characters "come to life" in Morrison's writing, Flex was apparently created by a psychic child with a green pen. The characters created in this child's youthful scrawlings, titled "My Greenest Adventure", apparently came to life. Amongst Flex's "Greenest Adventure" siblings were the villainous Waxworker and the heroic Fact. In 1996, Flex Mentallo received his own four-issue mini-series written by Morrison and illustrated by Frank Quitely. Although ignored by the Charles Atlas company at the time, it was later brought to the company's attention by a fan of the comics. Charles Atlas company president Jeffrey C. Hogue was unhappy with its likeness being used this way, and filed a trademark infringement suit against DC Comics. DC submitted a motion for summary dismissal, which was granted on the basis of fair use using the parody defense. DC has reprinted Flex's initial appearances, including the Charles Atlas parody, in the third and fourth collections of the Morrison Doom Patrol stories, "'Down Paradise Way" and "Musclebound". In 2012, DC reprinted the