A Super Mario Mystery Block!
A ? Block (alternatively Question Mark Block), also called a Question Block, a Mystery Block, a Prize Block, a brown Question Mark Box, or simply a ?, is a type of block found in midair, often containing coins, Super Mushrooms, or Fire Flowers, and may also be invisible
Source: https://www.mariowiki.com/%3F_Block
Included formats in download: .blend / .dae / .obj / .stl / .fbx / .gltf
BLEND (Blender, filesize: 881 KB), OBJ (OBJ, filesize: 1.72 MB), FBX (Autodesk FBX, filesize: 1.72 MB), GLTF (glTF, filesize: 1.72 MB), DAE (Collada, filesize: 1.72 MB), STL (Stereolithography, filesize: 1.72 MB)