Mushroom Fields (Mushroom Island) rank among the rarest biomes found in the Overworld. Generating exclusively as isolated landmasses completely surrounded by deep ocean, Mushroom Fields make up only a small fraction of the Overworld's total surface area, making a natural spawn within one exceptionally unlikely. Because these islands form in areas with the lowest continentalness values, ocean monuments are a common sight in the surrounding deep ocean waters.
The terrain of Mushroom Fields is blanketed in mycelium rather than standard grass blocks, and both red and brown mushrooms grow in dense clusters across the surface. Notably, mushrooms here can spread and survive under full sunlight. Huge mushrooms — more commonly found in dark forests — also generate here in numbers large enough to provide a steady supply of mushroom blocks. The warm temperature of 0.9 and maximum downfall value produce a rich, deep green foliage coloration similar in appearance to jungle biomes.
Mushroom Fields serves as the sole natural habitat of mooshrooms, the mushroom-covered variant of the cow. One of the most distinctive characteristics of Mushroom Fields is the complete absence of naturally spawning hostile mobs — this protection extends underground into caves and mineshafts beneath the island. Hostile mobs can still appear via monster spawners, raids, or lush cave sub-biomes that occasionally generate below the surface. In Bedrock Edition, only mooshrooms and glow squids spawn here naturally, and water takes on a light gray tint rather than the usual blue.