Podzol

Podzol is a dirt-type block that naturally blankets the surface of the giant tree taiga and bamboo jungles, along with their respective variants.

Obtaining
Podzol can be broken using any tool or by hand, but the shovel is the quickest. It can be obtained using a tool with Silk Touch, otherwise it will drop dirt instead.

Natural generation
Podzol generates only in giant tree taiga and bamboo jungle biomes, as well as their respective variants.

Endermen
Endermen can pick up podzol blocks, and will drop the block they are holding if killed.

Large spruce tree
$$, podzol replaces grass blocks, dirt and coarse dirt around a large spruce tree when it is grown from 4 saplings.

Trading
Wandering traders have $1/6$ chance to sell 3 podzol for 3 emeralds.

Usage
Like mycelium, podzol allows mushrooms to be placed on it no matter the light level, which allows the growth of huge mushrooms. Unlike mycelium, saplings, all kind of flowers and sugar canes can be placed on it normally.

Unlike grass and mycelium, it will not spread to adjacent bare dirt blocks.

Trivia

 * Unlike other similar blocks, podzol will never spread to dirt blocks, nor will it turn into dirt if a solid block is placed on top of it, no matter how long the block remains on top of it.
 * Similarly, neither grass nor mycelium can spread to podzol.
 * Podzol can be picked up by endermen.
 * In real life, podzol is a type of acidic, infertile soil found in subarctic taiga biomes and pine forests. Podzol literally means "under-ash" in Russian because it contains a layer of ashy soil that has been drained or leeched of nutrients. This explains why it does not spread like grass or mycelium as it is not an actual plant or fungus, nor can grass or mycelium spread onto it because it is infertile.