Wither Mushroom for the Nether

Though it is widely considered and heavily implied that the Wither is the boss mob of the Nether, the Wither is currently only represented by a single feature within the Nether, that being the wither skeleton. Though the wither rose could be used for this purpose if added into natural spawning in the Nether, that would take away some of the reward of it being exclusive to the Wither fight, so I instead suggest the addition of a new mushroom, the wither mushroom/withershroom. It would generate naturally in throughout the Nether and function very similarly to the wither rose when placed on the ground, giving a short wither effect when stepped on, though unlike the wither rose it wouldn't be able to craft black dye nor make a wither mysterious stew, however it could be placed into a mushroom stew recipe to create a wither stew, which gives the wither effect for longer than the mysterious wither stew, but displays its withering nature clearly.

The wither mushroom would be able to be farmed, being able to be grown into a large wither mushroom, though standing under it has a chance to wither those below it. In addition, feeding a brown mooshroom wither roses might have a chance to turn it into a wither mooshroom, which could be hostile, though still breedable. The wither mushroom would not be able to grow in the overworld, however, so the player would be forced to farm them in the Nether should they want to, unless they want to deal with the hostile wither mooshrooms.