The costume I'm going to submit is a DISHWASHER!!!
All you need to do is take a box and cut three corners of one side so it acts like a door.
Next (since you can see your body through the hole) you take some paper plates, plastic utensils, and paper cups and tape or glue them to a peice of cardboard the size of the opening of the "door". Then draw the racks that hold the dishes and utensils.
Then you put some holes on two of the corners of that peice of cardboard.
Thread some string or thin rope through the holes and hang around your neck.
Next cut a hole the size of your head in the bottom of the box(the side where the door opens down).
Put the box over your head and when you open the "door" you can see the dishes.
1. You can draw the dials of the dishwasher on the box above the door.
2. If you tape some string on the corner of the door and where the corners where the door opens the door will stay open instead of falling to your ankles or knees.
3. You can cut the plastic cups in half if they are going to stick out of the door.
4. If you don't have the utensils or the peice of cardboard just (don't cut out the door in the box) just find a picture of inside a dishwasher and enlarge it and tape it to the front of the box.
Thanks to Nicole for this very unique idea!