Aether

The Aether is a mini-biome that contains a large pool of Shimmer. It also has a unique feature which causes all fully dark blocks to appear as a background with stars, resembling the background of Space. The Aether is located underground on the Jungle side's outer fifth of the world, usually below the Ocean. It can be found in the Cavern layer anywhere from 100 to 2000 blocks down depending on the world size. It's most commonly found a little bit above the layer where lava begins to appear.