This adds a block that will rapidly spawn mobs in the darkness with some additional config options. It is made by sneak clicking a wither rose on normal dirt (can be disabled in config)

If Unstable Tools is installed, it can be made through the division sign ritual as well.

Sneak rightclicking the earth with an empty hand will show what mobs can spawn on it, handy for structure based spawning such as witch huts and nether fortresses.

min tick time between spawns (default 50)
max tick time between spawns (default 250)
mob cap - mobs stop spawning from cursed earth above this amount (default 250)
force spawn - mob spawns ignores restrictions such as light level or elevation (default false); removed in 1.20+
Mob blacklist - these mobs won't be spawned from cursed earth. cursedearth:blacklisted
cursed earth dies in sunlight (default true)
spreads naturally in darkness (default true)
spawn distance - minimum distance that players have to be before cursed earth spawns mobs (default 1)
cursed item - what item can be right clicked on dirt to make cursed earth. cursedearth:cursed_item default minecraft:wither_rose

* (Client only) Color of grass.