For Forge, requires Atlas Lib.
Invasions
On a configurable nights hordes of monsters will attack your base in waves from midnight until morning, with the encounterable mobs and times of day also being configurable.
Infection
If enabled players and horses can be infected after being hit by a zombie, turning into a zombie after 5 minutes have passed or they die with the infection.
In a players case this will kill them and spawn a zombie player in their place.
This infection can be cured with a golden apple with the default settings, but can be configured to be any item which can be consumed, but not reversed.
Optional settings that are enabled by default extends this to villagers, preventing zombie villagers from being cured.
Has an option in the config to add any zombie variants of other mods mobs to the list of entities that can become zombified, providing there is a corresponding zombie for it to convert into.
Zombie Players
When a player dies from infection or dies when an optional setting is enabled a zombified version of that player spawns in their place, containing all their items, or when underwater a drowned version.
By default zombie players are immune to sunlight, but this can be disabled in the config.
Other Misc Tweaks
Optional settings to make zombie horses a hostile mob (enabled by default) and to prevent undead mobs from burning in sunlight (disabled by default).
Special thanks to bstylia14 for the original mod concept and for providing ideas and help during development, as well as Ski_Z for helping find a lot of bugs and giving mod suggestions.
1.12 requires mixinbootstrap.