Blood Moon

A Blood Moon is an event that occurs only at night with a 1/7 (14.29%) chance, possibly even multiple times in a row. It can occur if at least one player in the world has >120 health and there is a moon in the sky (all phases except new moon). The chance of a Blood Moon rising increases if:

The player entered the distortion/crimson zone or jungle;
Holy Lands are located near the player (or the player lives in them) (hardmode);
The character holds a water candle;
The battle potion has been drunk.

As the night of the Blood Moon approaches, the message "The Blood Moon is rising" appears on the screen. The sky, water, and the moon itself take on a bloody hue. Monster numbers double, and zombies can open doors, leading to a massive assault on ground-based structures.

During the Blood Moon, the same music plays as during the meteorite.

Well-armed players can profit handsomely from this event by killing zombies and collecting the resulting coins. However, players with basic weapons are advised to block off doors with blocks and wait until the night ends.

During the Blood Moon:

All rabbits, penguins and goldfish turn into corrupted or bloody ones;
The death-grass blooms and produces seeds;
Additional items are sold by merchants;
During a blood moon, there is a chance for the Eye of Cthulhu to appear;
During a blood moon, there is a high chance of Gemini, Annihilator, or Skeletron Prime spawning if you are playing in hard mode;
Zombies move in groups of 2-6 individuals and open doors, but only from themselves; if you block a door inside a house with furniture, the zombies will not be able to open it;
With update 1.2 the water turns blood red;
With update 1.2, all coins stop dropping from mobs that spawn through statues;
With update 1.2, the copycat may appear on the surface;
The blood moon may increase the chance of a solar eclipse occurring;
Raindrops also turn blood-colored;
Female NPCs, with the exception of the party girl, begin to behave aggressively;
With update 1.3, two monsters appear that are not found anywhere else - the Drippler and the Blood Zombie;
With update 1.3, all colors change except for the color of grass, as well as orange/yellow armor and weapons/tools.

There are several ways to survive in a house without fighting monsters during this event:

1. Place a torch or furniture just outside the door, and zombies won't be able to open it, but some other mobs from other events can simply break down the door.

2. Make a 2x2 depression in front of the door (for zombies to fall into), so they'll only be 1/3 of the way to the door (the character's height and the zombie's height are equal to 3 blocks), and they won't be able to break down the door, but will only be able to jump around it.

3. Barricade the door from the outside with dirt blocks (or any other blocks).

Mobs

The following monsters appear in this event: