she had loved going trick-or-treating with her mom and dad when she was a little girl , seeing the looks on the faces of the other trick-or-treaters when they saw her mom and dad in their costumes ... of course , she realized now that her father 's costume had n't been a costume at all , and hard on the heels of that thought came the astonishing realization that her mother 's witch costume had n't been a costume either ... funny , she 'd never thought of that before .