Huge mushroom

A Huge Mushroom is a naturally occurring structure on Mushroom Islands and Roofed Forests. They are composed of mushroom stalks and either red or brown colored blocks for the cap. These blocks provide a valid spawn area for hostile mobs, and may be destroyed by hand to yield 0-2 normal mushrooms. The texture for the blocks which make up the cap depends on their position on it; for example, the corner block of the brown variety has 3 sides with the brown texture and 3 sides with the pore texture, while a block in the middle of the cap has only its top face covered with the brown texture and the others covered with the pore texture.

As of snapshot 14w25a when harvesting mushroom blocks with Silk Touch enchantment they drop blocks with corresponding mushroom texture (red or brown) on all sides rather than the one with spores.

Growth
Huge mushrooms can be grown by applying bone meal to a small red or brown mushroom that is planted on dirt, grass, podzol or mycelium; this works in any dimension. In open daylight, it requires more bonemeal on dirt or podzol than on mycelium to grow. Can only be grown in darkness (except if grown on mycelium or podzol.) (Note that only the small mushroom's original square needs to be dirt/grass/mycelium/podzol.) The axe is the best tool for destroying huge mushrooms. When destroyed, large mushroom caps and stalks have a chance of dropping small mushrooms of the same type they were grown from. Each giant mushroom can be expected to drop 2-25 small mushrooms, making this a valuable source of food.

A huge mushroom, brown or red, may grow to be 5, 6, or 7 blocks tall; no taller or shorter. They require a 7×7×6 to 7×7×8 space to grow depending on their height, not counting any spaces occupied by torches, ladders, etc. The top of the mushroom is always the same dimensions, but the stem may vary to be 4-6 blocks. However, the bottom-most layer (where the mushroom is placed) only requires blocks immediately adjacent to the source mushroom to be free, not counting diagonal blocks.

A huge mushroom will only grow if there is sufficiently low light, or if grown on mycelium or podzol.

Whenever bone meal is used on a mushroom, it randomly selects a size to attempt to grow. The maximum height that will succeed is one less than the amount of free vertical rows available above the mushroom; thus, if a block is placed 7 meters above the mushroom, anywhere in the 7x7 row, it can only grow to be 5 blocks tall. If the game selects it to be 6 or 7 meters tall, the bone meal will fail on that attempt, similar to how it behaves with tree saplings. This allows the player to force huge brown mushrooms to always be 5 blocks tall, but may consume significantly more bone meal due to failures.

A huge mushroom will not grow above the height limit.

Huge brown mushrooms
Huge brown mushrooms consist of a single stalk in the center, with a 7×7 canopy of brown mushroom blocks at the top with the corners missing.

Due to the space requirement matching the size of the canopy at the top, it is possible for a huge brown mushroom to grow with its canopy directly touching a mushroom next to it. This gives explorers the ability to quickly assemble platforms out of huge brown mushrooms, which affords a sleeping platform safe from mobs when illuminated (a single torch in the center is sufficient) or even the base for a house.

Huge red mushrooms
Huge red mushrooms, like their brown counterparts, have a single stalk in the center, but a different canopy, composed of five 3×3 slabs of red mushroom blocks arranged above and around the stalk, forming a 'dome'. Even though the space requirement is the same, the actual huge red mushroom only ends up being 5×6 blocks in area, so subsequent ones can be grown closer together than brown ones.

Due to their shape, huge red mushrooms can be used to build a basic hut, either by filling in the space between the cap and the ground, using pistons to push the cap of the mushroom to the ground, or by digging a large enough hole to accommodate a huge mushroom so that the cap intersects with the ground (may take multiple attempts; see above). Due to the height mechanics, one can always force them to be 5 blocks tall with a block 7 blocks above, so one can simply dig a hole in the ground, place a red mushroom, and dig out the 4 adjacent holes. While this may also take multiple attempts, the resulting huge red mushroom will be guaranteed to properly align with the ground.

Farming
See the above link on tutorials on how to farm huge mushrooms.

Biome occurrence
Large mushrooms will always appear in a mushroom biome or "mycellium island". They also appear in Roofed Forest along with Dark Oak Trees. Large mushrooms may also appear naturally at random in other biomes (excluding desert, mesa, or plains). These mushroooms will never appear naturally inside caves or ravines.

Video
''The narrator of the video says that huge mushrooms spawn naturally only in one biome. However, they now spawn naturally in two biomes. The video was made before huge mushrooms were able to spawn in Roofed Forest.''

Trivia

 * If farming giant mushrooms indoors, use a 9x9x8 space, since torches on walls block mushrooms and the extra space is needed. Alternately, use a 7x7x8 space and put torches in a one-block deep niche set into each wall.
 * The texture used for the sides of the stalks is a re-colored version of the bark texture used for spruce and oak wood.
 * If bonemeal is used to grow a huge mushroom, it can grow where the player is standing, causing the player to take suffocation damage.
 * The huge mushroom can be used as an emergency shelter. If a player has bonemeal and a mushroom, they can grow one instantly and sleep inside it after blocking off the bottom, surrounding area.  This makes bonemeal and mushrooms ideal to have for adventures away from home.
 * Huge Mushroom blocks with a data value of 15 have a texture that has the side of the stalk on all sides.
 * The Huge Mushroom can be used in a Furnace, giving time for smelting 1.5 items like the wood.