Due to their bad influence on other Cookies, each of them got a curse for their behavior. If they did not follow the curse, they'll die or either suffer from their previous actions. Reluctantly, they all accepted their curses, unaware of how hard it would be — for them, at least.

Black Sapphire Cookie wasn't allowed to spread rumors anymore.

Candy Apple Cookie wasn't allowed to spread lies anymore.

Yet as for their master — Shadow Milk Cookie, he had to be less deceitful and accept the truth.