Blood Moon

"You can tell a Blood Moon is out when the sky turns red. There is something about it that causes monsters to swarm."  - The Guide 

There is a 1/7 (one in seven) chance of a night being a Blood Moon night. The player will recieve a notification in the bottom left of the screen "A Blood Moon is rising" and the sky will turn red. (This is only a probability, it does not mean only one night in seven will be a Blood Moon, it could be multiple nights back to back.)

During a blood moon the spawn rate of monsters increases and Zombies gain the ability to "knock down" doors, however they only open it, they do not destroy it.

It is advisable during early gameplay to stay somewhere out of the reach of monsters during a Blood Moon.