Mushroom Fields

There is nowhere safer. Hostile mobs cannot spawn on mushroom fields at all, not at night and not in the shade of the giant mushrooms, and a zombie siege never starts here, which is true of this biome and of no other.

Mycelium replaces grass, red and brown mushroom blocks grow to the size of trees on their stems, and mooshrooms graze between them four to eight at a time. They are the entire spawn list and they live nowhere else.

It is one of the rarest biomes in the game and can sit thousands of blocks away, an island out in the ocean instead of against the land. Temperature 0.9 with humidity 1 makes it warm and humid, so rainfall rather than snow, and the surrounding climate means no two worlds put it in the same place. minecraft:mushroom_fields dates back to Beta 1.9 Pre-3 and 1.21 still generates it.

It is Overworld land that is never attached to any. Deep Ocean and Warm Ocean are its only neighbours, which is another way of saying it is an island.

It is very rare and almost always an isolated island surrounded by ocean, far from other land; explore the sea to find one.

Extremely rare, and open water is the only road to it, so a boat and food for a long crossing come before anything else. Mycelium on a shore in the middle of nowhere, with mooshrooms standing on it, is the confirmation. No portal is needed, but a plan is. Distance is the one reliable measure here, since no commands are involved: watch the horizon and keep sailing.

One animal, and it exists nowhere else. Mooshrooms fill the spawn slot outright, four to eight at a time, and this is the biome to visit if you go looking for one.

A mooshroom can be sheared for mushrooms, which turns it into an ordinary cow, and milked with a bowl instead of a bucket for suspicious stew. Struck by lightning, a red one turns brown and the stew changes with it.

Nothing hostile spawns on mycelium, day or night, which makes this the only surface in the game where a mooshroom farm needs no lighting and no walls. The quiet residents are mooshrooms, for example the red ones that turn brown under lightning. Come here if you want a mooshroom, because nowhere else has one.

Mooshroom

Mycelium is the block, and it grows here and in no other biome in the world. It spreads like grass, it keeps grass off, and mushrooms stay put on it in full daylight, which is why the giants stand out in the open here.

Red Mushroom Block, Brown Mushroom Block and Mushroom Stem all come off those giants, and all three are blocks only a couple of biomes grow. One giant mushroom is a chest full.

Nothing hostile spawns on mycelium at all, at any light level, so this is the one island where a base needs no walls. Fire burns itself out faster here as well.

The island plays by rules that no ground elsewhere does, and other biomes do not come close: the mycelium is why. It gives mooshrooms the only ground they spawn on, and a handful of them is beef, leather and stew without a fence.

Red Mushroom Block, Brown Mushroom Block and Mushroom Stem are the three mushroom blocks that a single giant mushroom hands over.

Few islands are this safe to sleep on, and few biomes are this hard to run into by accident.

Mycelium

Red Mushroom Block

Brown Mushroom Block

Mushroom Stem

The safest biome in the game is also one of the emptiest. Nothing built is tied to mushroom fields, so mycelium ground and giant mushrooms are the whole of what an island like this rewards you with above the surface.

That safety is the actual prize. Hostile mobs cannot spawn on the mycelium at all, day or night, so a base built here needs no lighting and no walls. What it does need is caution below ground, because the world still puts mineshaft tunnels, dungeon rooms among those tunnels and a rare stronghold under the island without asking, and the mobs excluded from the surface are perfectly happy down there. Safety and scenery are what exploring rewards here rather than buildings, while the dungeons and mineshafts dug beneath the island, an occasional stronghold with them, were generated with no regard for what grows above. Generation of that kind ignores biome boundaries, island or not, so such a tunnel is as unwelcome as anything gets up here.

Mushroom island vegetation is placed by noise rather than by count, so the giant mushrooms thicken and thin across the biome instead of per chunk. The two small mushroom passes are wildly uneven: brown on one chunk in four, red on one chunk in 256. Forty three passes in total, and no tree pass among them.

Zombie sieges cannot happen on the mushroom fields, and no other biome in the world has that exemption. A village built here can never be attacked by a siege.

Mooshrooms are the only thing that spawns, they have no temperature variant, and the island is still on the stronghold list.

Nothing is built on the mycelium. No village, no outpost, no ruin: the island is left exactly as the terrain generator made it.

Underneath it the ordinary mineshafts, a possible stronghold and the chambers in their -40 to -20 band carry on as if the surface were normal.