Crimson Heart

Crimson Hearts are floating, pulsing red hearts found deep in the branches of the Crimson. A world with Crimson features several Crimson Hearts, and destroying some of them is often a crucial step in game advancement. This can be done using any Hammer, or Bombs/Dynamite. Crimson Hearts release a fair amount of their own flickering light, similar to Demon Altars, which helps players spot them underground.

Crimson Hearts are usually located at the ends of the branches that split from the main circular room of a Crimson area, kept inside small rooms of Crimstone Blocks. In order to reach them the player may use explosives, a Nightmare Pickaxe, a Deathbringer Pickaxe or better, or Purification Powder.

Crimson Hearts are the Crimson-equivalent of the Corruption's Shadow Orbs. Like Shadow Orbs, the third one destroyed will summon a boss, the Brain of Cthulhu.

Consequences of destruction

 * Each Crimson Heart drops items when destroyed.
 * The first Crimson Heart you break on any given map will always drop an Undertaker and some Musket Balls. Carrying the Undertaker or Musket Balls will fulfill the criteria for the Arms Dealer to arrive.
 * The first Crimson Heart broken also fulfills one of the two criteria for a Goblin Army to attack, which has a 1/15 chance of occurring on each subsequent day (you will also need to have found and used at least 5 Crystal Hearts in order for the Army to begin invading)
 * Each Crimson Heart destroyed carries a chance of causing a Meteorite to land. If destroyed between dawn (4:30am) and midnight (12:00am), there is a 50% chance that a Meteorite will fall at the next midnight. If destroyed between midnight and dawn, there's a 50% chance that a Meteorite will fall immediately.
 * The third Crimson Heart destroyed summons the Brain of Cthulhu, which spawns immediately and attacks the player. Brain of Cthulhu is re-summoned with every third Crimson Heart destroyed.

Messages
The following messages appear upon destruction of Crimson Hearts:
 * First Heart: "A horrible chill runs down your spine..."
 * Second Heart: "Screams echo around you..."
 * Third Heart: "Brain of Cthulhu has awoken!"