This Mario papercraft is a Thwomp, an animate cinder-block found mostly in the Mushroom Kingdom, the paper model was created by headdog. Thwomps are spike-encrusted living stones that are usually rectangular in shape and made their first appearance in the game Super Mario Bros. 3.
Thwomps typically attempt to fall on and flatten or squash whoever passes below them, although some move horizontally or diagonally as well. They can only be defeated by being touched by Mario when he is powered up with a star, uses hammers as Hammer Mario, turns into Statue Mario, uses a Gold Flower, or when Mario is giant. It is suggested in Mario & Luigi: Partners in Time that Thwomps may in fact be born from volcanic activity. [Source: Mariowiki]
You can download this mario paper craft model here: Super Mario Bros. 3 - Thwomp Free Papercraft Download