Crimson Key Mold

The Crimson Key Mold is a rare drop used to craft the Crimson Key, which is in turn used to unlock the Crimson Chest in the Dungeon. The mold can be found from any monster in the Crimson biome with a 1/4000 drop rate, or a 0.025% chance.

Farming

 * A good way to farm for the key mold is to farm the Brain of Cthulhu because the Creepers count as kills.
 * Another good way to farm for the key mold is to create an artificial Meteorite Biome and stand in honey with Turtle Armor.