How to build an XP farm from a spawner in Minecraft
Dungeons are small Cobblestone and Mossy Cobblestone rooms underground with a Monster Spawner in the middle.

Mossy Cobblestone is cobblestone overgrown with moss, typical of dungeons and jungle temples.
It is made with the Crafting Table from Cobblestone and Moss Block (other recipes also exist). It is mined with a pickaxe.
Combine Cobblestone with a Moss Block or a Vines. It has slabs, stairs and walls, gives old builds a weathered look, and copies the Wild armor trim.
Cobblestone + Moss Block → Mossy Cobblestone
Cobblestone + Vines → Mossy Cobblestone
// Slots with several items cycle through every accepted option.
Dungeons are small Cobblestone and Mossy Cobblestone rooms underground with a Monster Spawner in the middle.
At the Crafting Table: 1 × Cobblestone and 1 × Moss Block give 1 × Mossy Cobblestone. Mining the block drops it.
It gives builds an old, overgrown look. It is an ingredient in 4 recipes, made at the Crafting Table and Stonecutter; for example Wild Armor Trim.
The fastest tool is the pickaxe.
Placed under a Note Block, Mossy Cobblestone gives the Bass drum sound.