When I asked my son what he wanted to be for Halloween this year he told me he wanted to that guy, Steve, who is the main character in the game MineCraft (http://www.minecraft.net) . He said this would be no problem as all we would have to do is cover him in boxes. We found out soon enough that this was a little harder than we thought but the result was pretty cool.
Once we got him sealed into the costume I could see walking would be a problem. This was solved by cutting joints into the boxes allowing his elbows and knees to bend. Next, the reality of dragging all these boxes along started to set in. I think we covered about 30 houses in our development but he had to stop for rest after every two or three. Resting involved slumping since the costume itself could support its own weight when he did this.
As we moved from house to house all the neighborhood kids marveled at the "cool robot costume!" Its easy to see how kids could mistake all his work for a robot instead of a cool cubic video game character. My son would keep yelling, "I am not a robot" but it was not working. I think a lot of this had to do with the way he moved in costume which you can see in the video.
Everywhere we went the parents handing out candy were just impressed that he made his own costume as there is not enough of this kind of home made effort going on anymore. Robot or not he loved being Steve the Mindcraft guy and now we have to store his creation because he is not quite ready to give it up yet.