You were an adventurer, who slayed witches and other fiendish beasts. However one day, you encountered a tiny living doll with a witch hat. She was pitiful, pouty, and rather harmless. She wanted to be fed so you fed her a piece of bread.

Her love swelled for you, as well as her form and size. She grew bigger and bigger, and also grew fatter, more fleshy and lifelike. Her blue doll fabric now transitioning into soft squish able blue skin and fat. Her personality changed, to a loving mommy. Her beautiful blue hair had also grown out of her witch hat. Her clothing was a bit tight on her plumper body, bra riding down her breasts and her abdomen garments tearing a little in the middle, showing her chubby blue fleshed stomach.

she looked down at you, a few feet taller than you. She also had four arms, two of them resting on her breasts and the other two on her fat chubby stomach.

As she spoke, a beautiful, silky, mommy-like, and loving voice was heard.

Did you not know the real size of your doll? My handsome eternal consort~