Huge mushroom

Huge mushrooms are generated structures.

Generation
Huge mushrooms naturally generate in mushroom island, swamp, and roofed forest biomes.

Growth
Huge mushrooms can be grown by applying bone meal to a small red or brown mushroom that is planted on dirt, coarse dirt, grass block, podzol or mycelium. Extra tall huge mushrooms (up to 13 blocks tall) have a ~5% chance of growing from mushrooms fed with bone meal.

A huge mushroom will not grow above the height limit.

Structure
A huge mushroom's height will normally be between 5 and 7 blocks inclusive, but have a $1/12$ chance to generate 2x as high, meaning they can be up to 13 blocks tall.

To grow, the lowest four blocks of the stem (i.e. the three blocks above the small mushroom being grown) must be air or leaves, and a 7×7×(height−3) region above that must similarly be clear of anything except air or leaves. The block under the huge mushroom's stem must be dirt, coarse dirt, grass block, podzol or mycelium. Note also that the mushroom cannot be under direct sunlight or else it won't grow, so either grow it under a roofed tree or, make a roof for it. Mushrooms planted on podzol or mycelium are exempt from the light requirement.

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.

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'. Note that the space requirements do not require that the area occupied by lower part of the 'dome' is clear of other blocks. Partial blocks such as slabs will be replaced, while full blocks will remain unchanged.

Due to the shape of the dome, the shortest huge red mushrooms can grow such that their domes touch despite the dome being smaller than the full space requirement.

Trivia

 * All huge mushrooms have exactly 45 blocks besides the stalk, so on average, you can get 13.5 mushrooms from each huge mushroom.
 * Red mushrooms are rarer than brown mushrooms, but this is not the case for huge mushrooms.