Moon Lord

"Impending doom approaches..."

Moon Lord is a Hardmode, post-Lunatic Cultist boss. He is considered the final boss of the versions of Terraria.

Moon Lord can be spawned by destroying all four Celestial Pillars, or by using a Celestial Sigil. In both cases, he will then spawn a minute after the "Impending doom approaches..." appears.

See below for the Moon Bite debuff inflicted by Moon Lord.

While Moon Lord is alive, his exclusive Music will play.

Behavior
Moon Lord has two hands and a head that must be killed before his core becomes available for attack. He positions his two hands on either side of the player some distance away.

Each hand, as well as his head, contain a vulnerable eye-like target that is each periodically closed off and opened via an eyelid. These may only be damaged during their "open" states. Once these parts and his core are destroyed, the boss is defeated.

Moon Lord can teleport to players if all of them get too far out of range.

Attacks

 * Moon Lord's hands move away from the core and their eyes spawn several . After a couple seconds, they explode, dealing heavy damage. If the player is far enough away, they simultaneously charge the player before exploding, though they cannot travel at an angle higher than approximately 30 degrees in either direction.
 * The hand eyes also spawn multiple, which move in all directions for a short while, and then home in on the player. Like the Phantasmal Spheres, they cannot travel at an upward angle, so they can be evaded by swerving upwards. If they cannot get a direct lock and a player is in range then they will attempt to match the target's trajectory to stay in their path. They explode upon contact with a block or player.
 * The hand eyes also occasionally fire two in quick succession, which pass through blocks and lead the player, requiring swerves to avoid.
 * When attached to Moon Lord's head, the head eye periodically opens for a few seconds, and then fires a : a large laser that sweeps upward over the player. This is by far Moon Lord's most damaging attack. Afterward, the head eye blinks a couple times, and fires two (similarly to those of the hands), and then closes.
 * The mouth periodically attempts to attach a Tentacle to the player. The Tentacle can reach through solid blocks. Once attached, it spawns multiple, which are monsters that travel from the player to Moon Lord's mouth. Any Moon Leech Clot that reaches the mouth without being killed returns 1000 health to one of Moon Lord's parts (one that has not yet been defeated).
 * The Tentacle also inflicts the Moon Bite debuff, preventing any life-steal effects from weapons/armor like Vampire Knives or Spectre Armor for 14 seconds (16 seconds in Expert mode).
 * When a hand or head target is defeated, it becomes a thorny crevice that deals damage on contact.
 * Additionally, when a head or hand target is defeated, a spawns, which cycles through four different attacks:
 * The eye spawns, which behave similarly to when before the eyes were defeated.
 * The eye spawns 6 in a hexagonal formation around itself, which after a few seconds will charge directly at the player, dealing a significant amount of damage to the player. This is by far the dominant source of damage in the second phase and should be avoided by swerving/dashing.
 * The eye fires 2 at the player, similar to those from the hand eyes
 * Finally, the eye charges and fires a lesser Phantasmal Deathray, smaller and dealing significantly less damage. Like the boss' deathray, this ability can be easily blocked by a roof.
 * The eye dances outward in a spiral, dealing a small amount of damage upon impact.
 * Note that while the True Eyes of Cthulhu perform these attacks, they remain stationary, giving players more time to put distance between them and the eyes, and to see attacks coming.
 * He can teleport and attack players with all his attacks when another player dies in a group of 2 or attack the last player in a group of 3.

Tips

 * If you don't get sick from the Gravitation Potion, you will be moving vertically fast enough to avoid most of his attacks, but it might be difficult to hit his vital parts, unless you use homing capable attacks.
 * You can also use it to dodge the Phantasmal Deathray.
 * Using a weapon that can attack through blocks, such as the Solar Eruption, can mitigate incoming damage while making evasion less complicated. Two rows of blocks (one to run along and one above to protect from lasers) can be quite effective. Make sure the rows of blocks are separated widely apart so that you can avoid the Phantasmal Spheres that could come horizontally from the True Eye Of Cthulhus.
 * A large portion of Moon Lord's attacks, including the Phantasmal Deathray he emits from his head, are incapable of passing through blocks. Consider seeking cover to avoid these attacks during the fight.
 * The Moon Bite debuff, which prevents regenerative abilities, is reliant on a tentacle making contact with the player. It is possible to move outside of its maximum range, avoiding the debuff and allowing effects to once again heal the player.
 * It's best to kill the Head first, and then the hands. This will cause the eyes to come out of the hands at the second half of the fight, increasing your survivability during the first half.
 * Since the hands will begin to start dealing melee damage after they are defeated, running away on an asphalt sky bridge will become an issue if not properly prepared to dodge the hands.
 * It is unwise to use Vampire Knives or the Spectre Hood as the Moon Bite debuff occurs very often, which disables life steal from these items.
 * Moon Lord does not despawn if you go too far away from him. Rather, he teleports to where the player with the shortest distance from him.
 * You can use Minecart Tracks or Platforms going across your world to avoid the attacks.
 * Owning a Rod of Discord can provide a great deal of assistance, as it can be used to easily evade Moon Lord's Phantasmal Death Ray. Use it sparingly though, as Chaos State can kill an unaware user.
 * The Cosmic Car Key can provide a huge advantage, as it makes avoiding his attacks easier than on the ground, and also goes slightly faster than Moon Lord.
 * It is a good idea to use the Flairon or some homing weapons, because you can focus on dodging and you don’t need to aim as much since the projectiles will chase an undefeated part.
 * Simply having more players on the world will make things significantly easier, because although Moon Lord will have more health and heal more due to his leeches, making the fight much longer than normal, it will also lengthen how long the players can last.
 * The Cute Fishron is capable of mildly outrunning the Moon Lord under half health or after touching liquids; this can be used to avoid his Moon Bite debuff. However, care must be taken to stay just far enough away, but not so far as to trigger him to teleport to you.

Trivia

 * Despite a mid-development comment by Cenx that this would not be the case, Moon Lord resembles common depictions of, a creature first imagined by in his story, . Fans commonly speculated prior to the release of 1.3 that Cthulhu would be the final Terraria boss (which in turn arose partly due to an early concept design floated by the development team).
 * Terraria's final boss was originally going to be the Moon himself descending on the world, but Cenx later stated that this idea had been scrapped.
 * Despite being the final boss of the game, Moon Lord's monetary drops are less than the Wall of Flesh on normal mode, and absent on expert.
 * Due to the colors of the boss and the names of a few of his projectiles, this boss may have been designed from the Vortex Pillar.
 * Despite being the final boss, Moon Lord has the lowest amount of debuff immunities, being immune only to Confusion (tied with many other bosses who also share the same immunity).
 * Moon Lord's resemblance and relation to Cthulhu have a basis within Lovecraft's "Cthulhu Mythos" as Cthulhu has two brothers, an identical twin named Kthanid and a half brother named Hastur, both taking a form similar to Cthulhu's, though Moon Lord is more than likely in reference to Hastur as both have a trademark sign that signals his arrival (see the Celestial Sigil and the yellow sign) as well as the fact that unlike his twin, Kthanid is "as good as his brother is evil" making it unlikely that he would attack the player.
 * NPCs do not seem to be able to attack the Moon Lord.
 * According to Cenx, spriting the Moon Lord took over a month.
 * Despite having five eyes on his head, the Moon Lord's map icon only has three.

History
Mondherr Seigneur de la lune 달의 군주 Władca Księżyca Лунный Повелитель 月亮领主