Mud Block

A Mud Block is a Dirt-like Block that can be found Underground. Mushroom Grass Seeds and Jungle Grass Seeds can only grow on mud. When placing a Jungle Grass Seed on a Mud Block at below 0ft, you can create an Underground Jungle,  and when placing a Jungle Grass Seed at above 0ft, you can create a normal Jungle. Mushroom Grass Seeds will only grow at below 0ft.