Mushroom Operation.

Mushroom Operation.

Mushroom Operation is a process carried out by unknown (possibly unrelated) individuals to plant as many mushrooms as possible at spawn.

The essence of the operation is that the mushroom in Minecraft (and in 2Beta2T in particular) automatically generates new mushrooms if the light level is too low. And at spawn, the light level is extremely low, as the spawn is sealed by a giant obsidian cap.

Lavacast at spawn, covered in mushrooms.
See more details here.

Mushroom Operation is also carried out in the Nether.