Brain is an underground Mini-Biome type characterized by its Brains blocks. Its related surface biome is the Tentacle Biome. This biome makes up the entire underground portion of the Ruin, and is found nowhere else in the Starbound universe.
There is no way to access this biome other than traveling to the Ruin and digging down (or using Admin Commands to create a custom terraformer/microformer). There is an enormous empty space between the surface of the Ruin and this biome, so caution must be exercised when traveling here. (For strategies on how to make your way down here, see Ruin). Once the player reaches this biome, they must look for a structure with to one-way doors on either side. Here, they will end the game’s story.
There are no monsters or treasure in this biome.