The Mask is a fictional character who first appeared in the DC Comics' universe in the Wonder Woman series as a masked villain. She has the same name as a male character from the Dark Horse Comics whose secret identity is Stanley Ipkiss.
The Mask appeared in one of the last issues penned by Charles Moulton and published during Moulton's lifetime. (Other adventures written by Moulton that had been stockpiled continued to be published after his death, and still others were written by his family and published under his name.)
The appearance of the Mask -- a tormented woman who developed a split personality which caused havoc by trapping people in fatally rigged masks that resemble S/M tools -- draws on themes of psychology and bondage that recurred throughout Moulton's writings.
The Mask was a bold villainess who trapped her prey in rigged trick masks which would release deadly hydrocyanic gas into her victims' mouths unless the masks were unlatched with a special key.
Wonder Woman was drawn into the emotionally intense battles between millionaire industrialist and amateur trekker Brutus Close, his frail and tormented wife Nina, and his associate Fancy Framer one day when she was flying back from Paradise Island and came across a plane in distress. Wonder Woman rescued the woman piloting the plane and landed in her invisible plane's hidden hangar, an abandoned barn in the Northern Virginia outskirts of Washington, D.C. The woman pilot fled, but Wonder Woman investigated the plane wreckage and discovered a purse belonging to Nina Close. In her guise as Lt. Diana Prince, Wonder Woman delivered the purse to the Close residence, where she immediately realized the frail Nina Close could not possibly be the pilot. While there, she witnessed an argument between Brutus Close and Fancy Framer, bold outdoor adventurer hired to lead Close's expeditions. When Close accused Framer of stealing and crashing one of his planes, Framer left and angrily threatened to expose him as a fraud to the press he so extensively courted.
Diana was called back to the Close residence with word that the Mask had struck. A woman calling herself The Mask has invaded the Close residence and trapped Brutus Close in a fatally rigged mask, demanding $1 million in exchange for his freedom from the mask. Her ransom note insisted that he deliver the funds to the top of the Empire State Building.
When military intelligence officers Maj. Steve Trevor and Lt. Diana Prince accompanied Close from Washington to New York to deliver the ransom, they were shocked to see a woman fly by in Wonder Woman's invisible plane and lasso Close and the ransom money.
The Mask demanded more money from Close and similarly captured the Holliday College girls, demanding money from military intelligence.
Because her invisible plane had been stolen and used to capture Brutus Close, Wonder Woman deduced that the Mask had to be Fancy Framer, who she assumed to be the pilot of the distressed plane and thus knew the location of the invisible plane. She was shocked to realize that the Mask was really Close's wife Nina, a frail and tormented mouse of a woman who had developed a split personality during her marriage to the domineering Brutus Close.
The Mask reappeared in the Silver Age when a magical duplicate of her and several other opponents of the Justice League of America was used in an elaborate plot by the Demons Three to trick the JLA and free themselves. Close herself was still institutionalized at the time. (Justice League of America (vol. 1) #35.)
The Mask has recently reappeared in Wonder Woman (vol. 3) Annual #1 as a masked gunwielding villain. Narrative captions describe her as "The Mask, an abused wife who murdered her husband and now uses his fortune to empower similarly victimized wives and mothers."