Glowing Mushroom biome

Mushroom biomes are areas where Glowing Mushrooms are findable.

Surface Mushroom Biome
A surface level mushroom biome can be created by planting mushroom seeds on mud. If enough continuous blocks are created the background and music will indicate a transformation into the surface mushroom biome. On the surface the mushroom biome shows towering giant mushrooms in the background when it is not obscured by a wall. Giant mushrooms can grow to significant heights if room is allowed for them to grow, and can regenerate if chopped down.

It is known that the Truffle NPC can only have a house in the surface mushroom biome.

Enemies rarely spawn here pre-hardmode, except during a blood moon which creates several hardmode-equivalent spawns. For this reason it is not recommended for new players to create mushroom biomes close to their spawn point until they have sufficient gear. Some players have reported seeing Spore Zombies and Mushroom Zombies spawn at night, though whether this is due to hardmode, a blood moon or having a large enough biome is not yet known.

Underground Mushroom Biome
Underground mushroom biomes are found anywhere below 0 depth, including in pockets deep in the underworld. Potential enemies include black slimes, mother slimes, and cave bats, though whether enemies are specific to the biome or drawn from adjacent biomes is unknown. Similar to the surface biome during the blood moon and in hardmode more difficult enemies spawn which are unique to the mushroom biome. Underground the mushroom biome shows smaller mushrooms everywhere as its background, unless obscured by a wall. Giant mushrooms can also grow here if there is enough vertical space, though unlike surface giant mushrooms they typically appear without branches.

History
1.2: Glowing Mushrooms were given their own biome (including music, background, spawns, etc.) as well as the ability to be cultivated on the surface (above 0 feet).