Metztli

Metztli is a new take on the classic Blood Moon concept. Every night, there is a chance the moon will rise tinged bloody, and its eerie light influencing and mutating certain living things. Monsters will gain otherworldly powers, animals may go mad, and players are just as susceptible to the light as any wolf or zombie is. The reddish light of the Blood Moon may also draw out powerful new beasts from their secret dens, hunting under its glow. 

Rather than the typical Blood Moon mod features of "increase monster spawns", Metztli will instead both feature new monsters that can only be found on that night, as well as causing other mobs to get Cult of the Lamb-inspired effects. There is a reason to brave the Blood Moon as well. Rather than hunkering down in your base and waiting for it to end, the creatures afflicted by the Blood Moon, or the ones created by it, will drop new resources that can offer great power. In addition, certain new plants can appear that can herald the rising of a Blood Moon, the only way to predict when one is about to rise.