Doraemon: Explanations for the character's color change

The character Doraemon, the robotic cat from the 22nd century, was not originally blue. In various versions of the series' lore, the character was initially yellow and possessed ears.

There are multiple explanations for the change in color and appearance. One popular version from the 1995 film ‘2112: Doraemon is Born’ suggests that after losing his ears to a robot mouse, Doraemon accidentally took a ‘tragedy medicine’ instead of ‘happiness medicine.’ The resulting intense crying for three days and nights caused his yellow plating to peel off, revealing a blue body underneath.

Another explanation, dating back to the late 1970s in the ‘Doraemon Encyclopedia’ published by CoroCoro Comic, suggests that the shock of losing his ears caused him to turn blue from fright.