This mod requires terrablender and cloth config to function and can be used in any modpack!

Mushroom Caves

... can be quite big and are not much rare. They tend to like warmer climates.

Underground Mycelium Blocks

... are a weird mix of mycelium and stone/deepslate. They will actually spread mycelium to dirt, if the area is well lit up. If you want to renew them, right click on them with some bonemeal around stone/deepslate. They also don't like it when you place blocks above them.

Too much time might've been spent on these mechanics.

Glow Mushroom Caves

You might think these are more rare but they just like colder climates more. These biomes can spawn next to each other though. Did you know that the glowing only comes from the mushrooms and not the mycelium?

It even has a little config to change how rare or big these biomes are!