Prompt 1 Part 1: Aren't you a little old to be trick or treating?

Hi! I just ship Mabcifica so much and feel like it doesn't get enough love, so I'm going to write a few drabbles for it. Leave a comment if you have a prompt that you would like for me to consider writing.

Cover: http://liighty.deviantart.com/art/yuriz-516019486