Doom Patrol #90 (1964)

As the Doom Patrol relaxes during a period of quiet, their foes, the Brotherhood of Evil begin another plot to destroy the Doom Patrol and take over the world. Madame Rouge undergoes an experiment developed by the Brain and gains the ability to mold her skin into any shape imaginable, and stretch into any shape she wants and is sent to infiltrate the Doom Patrol in order to destroy them. When the Doom Patrol are called to fix a dam, Madame Rouge uses the absence of Elasti-Girl to disguise herself as the heroine. When alone with Robotman, "Elasti-Girl" knocks him into the dam below before disappearing. When the real Elasti-Girl arrives, Negative Man suspects trouble and the two find and rescue Robotman before fixing the dam. Returning to headquarters, the Chief deduces that there could be a traitor in their midst at anytime soon and has the group to be cautious during their coming missions. Later when the Doom Patrol is called in to rescue trapped miners, they send down Robotman to investigate. He is attacked by Madame Rouge, who has disguised herself as the living robot and buries him under a pile of rubble. Taking his place she tries to kill Elasti-Girl and Negative Man by sending the elevator crashing down but Larry manages to save themselves with his Negative Man form. The faux Robotman makes an escape and the remaining members of the Doom Patrol rescue the trapped miners and Robotman from the mine. For their next mission the Chief decides to go along with the group, before leaving he has them all establish passwords so that they can regularly check to see if they are really who they are at any time. When their next call for help comes from a ship full of explosive chemicals catches fire, the Chief orders Larry to send out Negative Man to help the others stop the blaze. Madame Rouge disguises herself as Larry and drags his unconscious body away. However when she tries to kill Larry with a gun, she realizes that a side effect of her powers is that she cannot kill someone that she is posing as because of a subconscious belief that she is really them. The Brain then instructs her to take the Chief's place. When the rest of the Doom Patrol arrive, Larry (revived) pretends to be a fake by "forgetting" his password. This allows him to get close enough to the "Chief" to land a punch before "he" can shoot and kill any of the members of the Doom Patrol. With her cover blown, Madame Rouge manages to escape from the Doom Patrol before they can capture her. With the real Chief recovered, the Doom Patrol return to base. While back in France, the Brotherhood of Evil is already busy planning their next attack on their hated foes.