This hand decorated cardboard box was used by Sharlto Copley as Chappie.
Chappie keeps his various trinkets (like his book & ‘Mommy’ doll) inside this to hide them from Ninja.
This particular box is marked as ‘Stand In’ and was used in the shots when held by Sharlto Copley in his motion-capture suit and in shots where the fine details wouldn’t need to be seen.