Guide:Farming Biome Keys or Key Molds

Make a set a corruption blocks (Ebonstone) (enough to allow you to summon the eater of worlds - best suspended in air to avoid contamination) near the environment kind you want to farm. Summon eater of worlds on the corrupted blocks then return to environment of choice. (just tested on 1.2.3.1, Eater of worlds dropped me a frozen mold.) However farming with Water candle and Battle Potion might prove more efficient in some cases. On account of testing - its somewhat preferable to use this for the corruption mold as most corrupt creatures that spawn are flying or burrowing so that slows the process down noticeably. The frozen and jungle molds are notably faster to gain via potion and candle.

OLD METHOD ... '''/!\ This page requires major testing and update since the 1.2.3 patch note says Meteor Head no longer drop loot in hardmode. /!\'''

= The methods listed below are now obsolete since the meteor heads no longer drop loots in hard-mode =

Farm Designs

 * It is preferred to build the farm underground, at least so far that the surface is not visible on the screen. This allows for a better spawn rate, and a higher spawn limit. (For best results, in the case of or Corruption/Crimson, make sure souls are dropping.)
 * All farming methods can be made more effective by drinking Battle Potions and holding a water candle. Note that placing and holding separate water candles stack.
 * All methods and techniques listed here are in no way documented to be the best. If you come up with a better method, please post it here as a guide.

Killing Machine
This method can be hard to setup but is very effective and can be done while using any gear. What you need
 * 14 spiky ball traps
 * Wire (with a wrench and maybe some wire cutters)
 * Three doors
 * A timer (preferably the 1 Second Timer)
 * At least 50 meteorite ore

The build

Dig out a medium sized room a little ways underground and place your materials like shown in the picture. The meteorite and wire can be placed however you like, just make sure the wire passes over every trap and the timer. The finished product might look something like this:



Pygmy Warriors
What you need
 * At least 50 meteorite ore
 * Pygmy Staff
 * Rope

Recommended (These items upgrade your pygmies, making you safer and increasing the efficiency of the farm)
 * Full Tiki Armor
 * Pygmy Necklace
 * Hercules Beetle

Assuming it's accessible, this setup is also a valid option:
 * Full Spooky Armor
 * Pygmy Necklace
 * Hercules Beetle
 * Papyrus Scarab
 * Necromantic Scroll

The Build

Dig out a small room underground and place down your meteorite in any fashion you like. Now place your rope so you easily can hang in the middle of the room. Now spawn all your pygmies and grab the rope. Like this:



While you are hanging on the rope and holding a water candle the water candle will not be visible.

The Aviary
What you need
 * At least 50-85 meteorite ore
 * Raven Staff
 * Wood Platform
 * One of the Hooks or something made from the Cobalt Shield to anchor yourself.
 * Full Tiki Armor or Spooky armor.

Recommended
 * Pygmy Necklace
 * Necromantic Scroll
 * Band of /Charm of Myths (not necessary if properly centered, but doesn't hurt to make sure).

The Build

This build relies one of hardest items in the game to obtain (The Raven Staff), but is extremely easy to set up. Simply go to the biome you want the mold of, go underground and build a box of meteorite like this:



Next summon as many ravens as you can (click inside the walls so they spawn inside). Make sure you properly center and anchor your character inside the box on the wooden platforms two blocks above the floor so the ravens have enough time to home in on any meteor heads that enter the box. Any loot should automatically be picked up and meteor heads should rarely, if ever, touch you.

Turtling
What you need
 * At least 50 meteorite ore
 * Turtle armor
 * Two or three buckets of honey

Recommended
 * Band of
 * Charm of Myths
 * Campfire
 * Heart Lantern
 * Any obsidian item to be immune to the meteor blocks or a bunch of blocks not to be in touch with the meteor blocks
 * Cobalt Shield or upgrades thereof to be immune to knockback

The Build

Dig out a small pond in the (artificial or natural) meteor biome to pour honey or water. 2 blocks deep and 2 blocks wide, pour at least 2 buckets in the pond in order to be considered immersed and instantly extinguish the On Fire! debuff. You know you're enough immersed when the Water Candle doesn't fit in your hand while you select it (don't worry, even if it doesn't show, it still grants the monster spawn bonus). The best: since the meteors crash in you, you immediately loot every drop and nothing is loss. Consider adding a campfire, possibly with a Heart Lantern, for maximum regeneration.



Mold specific farming
For all these methods, events such as pirate invasion, frost legion and pumpkin moon will help. Other aids increase monster spawn rate like Blood moon, battle potion and water candles. Note that these three buffs/debuffs stack and can be used for maximum efficiency.

Corruption Key Mold
The Eater of Worlds Boss segments all count towards the drop rate of 1/2500. Since the Eater of Worlds consists of 50 body segments there is a 1/50 (2%) drop rate for a key mold from the Eater of Worlds. With Hardmode equipment, spam summoning the EoW is quick and reliable.

Another, lesser, method is to kill worm type creature like the World Feeder with explosives. This will kill multiple segments at once, each dropping their own loot.

Crimson Key Mold
The Brain of Cthulhu uses a group of creatures called creepers to attack the player. Each Creeper has a 1/2500 chance to drop the Crimson Key Mold. Spam summoning the Brain of Cthulhu is not as reliable and fast as the corruption equivalent but is still fast.

Hallowed Key Mold
As the Hallow is most commonly the players home biome, to stop corruption/crimson, it is relatively easy to obtain the hallowed key mold. As the home biome, invasions tend to happen in it and can be of great help to get the key mold. There is no other method for farming hallowed key molds as of far.

Jungle Key Mold
Once in Hardmode, the jungle is much more dangerous to enter. There is no specific farming method in the jungle. Therefore, the best way to obtain the mold is to put water candles everywhere and drink a battle potion. An untested method is that bees spawned from hive blocks may drop the jungle key, but it is unlikely.

Frozen Key Mold
There is no specific farming method for the snow biome. A reliable method is to place water candles everywhere and drink a battle potion. Then kill everything. Note that corruption, crimson and hallow biomes take precedence over snow biomes. Stay away from the edges of the snow biome to stop monster having a chance to drop those key molds instead.