The Slime Cave is an underground biome in which the grass is dull blue, and the walls are made of Slime Blocks and Mud. It can be found inside any planet. You will also find that pools of Poison Water are common, making exploration dangerous for low-tier players. This is also the only place where you can aquire Cell Matter. It is aquired by smashing any of the two varying cell structures. The first appears to be a double helix with a bare inside. The second looks like round, light green balls connected by dark blue rods. It resembles a molecule . They both emit a faint light. You can also find Cell Chests that contain Blueprints for Cell furniture.