Population Control

This is a configurable mod that makes the following changes:

• Killing hostile mobs in a certain region reduces the number of mobs that will spawn in the future in that region.
• Mobs moving across chunks restore the mob population in that region.
• Players cannot use beds to sleep in regions with high mob population.
• Players cannot use beds to set spawn in regions with high population, unless the bed is currently exposed to sunlight.

In the Overworld, regions have vertical sections that don't affect each other. Specifically, there's one section for everything from Y=48 upwards, and 7 underground sections each 16 blocks tall. This means that killing a mob on the surface doesn't reduce the underground population and vice versa, and the same is true among different sections underground.