Mrs. Baker was the leader of an international counterfeiting gang.
Mrs. Baker was an elderly Caucasian female with gray hair and glasses with semicircular lenses. She wore a pink dress with a purple hood and cloak.
She seemed like a kind old lady when the gang first met her, but this was a front. She was actually a cold, sneaky, and callous person who was willing to kill to protect her counterfeiting operation, as seen when she attempted to lower Shaggy Rogers and Scooby-Doo into a car crusher at the auto-junkyard.
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The gang, Batman, and Robin were investigating a crate delivered to an old farmhouse which they originally thought was deserted when they met her. She claimed to know nothing about the crate or why it was delivered there. It contained a punch clown with phony money in it. Velma Dinkley found jeep tracks outside the house left by the men who delivered the crate. Mrs. Baker told them that they may have taken the jeep to the auto-junkyard, but she also warned them of a rumor that the spirits of the departed wander the junkyard at night. When they got there, they found no spirits, but a hooded figure who nearly killed Shaggy and Scooby by picking up a scrapheap they were hiding in and lowering it into a car crusher. When they returned to where the farmhouse was, both it and Mrs. Baker had disappeared.
They eventually solved the mystery of the disappearing farmhouse; it rotated underground and was controlled by a hidden lever. In a secret underground hideout beneath the farmhouse, they found the hooded villain again. When they captured "him", they asked what the hooded figure did with Mrs. Baker, only to discover that Mrs. Baker herself was the culprit. 
- Mrs. Baker was the first female culprit to be unmasked, although chronologically the first would be Prestina from the A Pup Named Scooby-Doo episode, For Letter or Worse.