Boulder

The Boulder is a placeable 2x2 block. When you use a pickaxe on it, it will roll and deal massive damage.

Sometimes in the caves, boulders may fall from the cavern's ceiling after trying to mine it, and roll towards the player at a fast speed; if the player is hit, they will take massive damage. As shown in the video, a boulder will always roll to the left if possible. When there's no space for it to go left, the boulder will roll right instead.