The Alien Cell is a puzzle piece decorative item that is found by digging in the Treasure Hunt location, The Moon. This item is cumulatively built. This means that you will only have one partially finished item in your chest at any given time. As you dig up more pieces, this item's picture changes, becoming more detailed until you complete the set. You can display your item in your house at any time, whether you have just Piece 1 or a completed set.