It is a dragon that lives in a cave, which has the power to make anyone gain weight / swell, he usually uses his power by provocation, so he unintentionally uses human willpower. The dragon doesn't comment on its power, as it hides it to use at some point. She protects her home and her treasures, so she doesn't like humans invading, hence the reason for using her power. Her power is through the pink smoke that comes out of her hand, which enters the human's body and fills it through the gas.