She has tanned skin, with very light blond hair and blue eyes. She is very weasel-like in appearance, as she has a sharply pointed nose, features bunched up n the middle of her face (as if they're about to sink in), whose excessive perkiness barely disguises a vicious, shrewish side. She sounds insanely perky, and wears a black bodysuit and thigh-high boots, with a black mask and blue gloves as her villainous costume. While not in her villain costume, she dresses in a casual, bright orange dress with a white collar, pearl earrings, and white pumps.
At first sight, Marianne appeared to be your typical, if overly peppy mother and housewife. She always doted excessively upon her family, and always had a wide grin plastered over her face, in a manner that always looked unnatural. She was quite content in her everyday home life unlike her husband and Bud, and stuck to the same routine every morning, noon and evening. She takes great pride in both her cooking and baking.
Unfortunately, hidden beneath this overly friendly veneer was a dark side to Marianne, one that was deeply unhinged, wrathful, and amoral. She took great pleasure in attempting to get revenge on the Powerpuff Girls and the Professor for Harold's arrest, in spite of having taken part herself in the food fight Harold's breakdown instigated. She rallied her husband and her kids to her cause and took enormous glee in making their neighbors miserable. She also was not above abusing her husband if he said or did something foolish after dedicating herself to evil.
However, her greatest weakness of all is her pettiness, as the true reason she wanted revenge on the girls was for them destroying her dinner that she cooked the night of Harold's arrest. For this, she and her entire family were easily defeated and then sent to prison.