Editing Terraria (section)

===Blood Moon===
At night, monsters come out. Zombies and Demon Eyes, mostly. On a Blood Moon, a somewhat uncommon event, evil is stronger; the Zombies and Demon Eyes hit harder (and sometimes mutate into abominations), and the Zombies gain the presence of mind to open doors, and Female NPCs get grumpy towards you because...ahem. Encounters for all monsters skyrocket. Suffice to say, the Zombie apocalypse is on, and your NPCs are in jeopardy unless you built your base well. (Hint: Two-door "airlocks" work just fine, since zombies can only open doors inwards.)  Good training for the much more dangerous rigors of Sieges and PVP, Blood Moons give you a real taste of a sustained assault. You must hold the line until [http://www.youtube.com/watch?v=EjazC45Qkww the morning sun vanquishes the horrible night].

God help you when these happen on Hard Mode. And don't go fishing unless you want more nasties to fight, including a miniboss in Hardmode.