It could be a representation of the fact that you feel that your mother is betraying you of the fact that you want her to be less controlling. The party could be a representation of her "letting loose" and effectively giving you more freedom, even if that isn't what you want. The betrayal to your father could be a betrayal to you, and the "Chucky's gonna kill you!" could be her controlling you. The acceptance of the proposal could be like an ultimate betrayal, but this is just a guess... Don't look too deeply into this.