Mycelium should be able to spread on Grass

Mycelium should be able to spread on Grass like how the Corruption spreads in Terraria.

Since this is minecraft it would not be able to take over worlds, ONLY on:

Grass

Dirt

Podzol

Maybe Coarse Dirt

Maybe Rooted Dirt

This would be a toggle-able option like TNT explodes or Fire Spreads.

The Mycelium would NOT extend Mooshroom biomes, as that would be too laggy.

Thank you for reading. :)