Preventing spawning in mushroom biomes

[Matthew Cline]

According to the wiki:

The enemies associated with the Mushroom Biome will spawn anywhere there is glowing mushroom grass, regardless of how much there is.

So to prevent spawning in a mushroom biome, do I merely have to put walls behind mushroom grass blocks and right next to mushroom grass blocks? Or do I have to put walls in everywhere that the mushroom biome music is playing?

 

[Mental Mouse]

Looking at the relevant spawning page, I think you'd need to wall off the entire space. The game picks any nearby tile, and if it's open space without a player-placed wall, it then looks down to find the floor. If the player is in Harpy/Wyvern territory, it doesn't bother with the floor.

The alternative to prevent spawning is to install town NPCs -- three resident NPCs on-screen will prevent all enemy spawns.

 

[Matthew Cline]

I set up a mushroom biome far up off the ground, surrounded by back walls and with back walls behind each mud block. This has prevented any mushroom biome monsters from spawning.