Daytime Hostile Mobs is designed to make the game more challenging during the day by spawning mobs that would usually only spawn at night. Players bypass the night by simply sleeping in a bed, so why not make the monsters appear during the day as well? Note that there aren't as many monsters during the day as there are at night. The mod also prevents monsters from burning in daylight, and spiders remain hostile regardless of daylight or light level.

How it works:

Eligible passive mob spawns sometimes swap with a hostile mob spawn instead. For example, a pig that tried to spawn could spawn a zombie instead, creating a daytime world that can feel closer to night-time danger. Why do it this way instead of just spawning the hostile mobs separately? Because Minecraft already has reliable daytime passive spawn placement during world generation. If we tried to spawn hostile mobs normally in daylight, vanilla’s hostile spawning rules would block or despawn them because of light level, time of day, and spawn caps. Also, this method makes it easier to control the frequency at which hostile mobs spawn.

Eligible passive mobs have a 50% chance to swap into a hostile mob when they spawn. The eligible passive pool is:

`ARMADILLO`, `CAMEL`, `CAT`, `CHICKEN`, `COW`, `DONKEY`, `FOX`, `FROG`, `GOAT`, `HORSE`, `LLAMA`, `MOOSHROOM`, `MULE`, `OCELOT`, `PANDA`, `PARROT`, `PIG`, `POLAR_BEAR`, `RABBIT`, `SHEEP`, `SNIFFER`, `TURTLE`, `WOLF`

Hostile replacements are weighted to feel more like normal night spawning rather than each monster having equal odds. Common picks include zombies, skeletons, spiders, and creepers, while endermen, witches, and zombie villagers are rarer.

Biome-specific replacements are included too:

-> `HUSK` can appear from swaps in desert biomes.
-> `STRAY` can appear from swaps in snowy biomes.