Main article: Bosses
The Moon Lord is the final boss of Terraria as of version 18.104.22.168, and drops a majority of the endgame items, such as the Meowmere. It also drops the end-game ore, Luminite, used to craft many endgame armor sets and tools. He is summoned by defeating all four of the Celestial Towers from the Lunar Events, or by using a Celestial Sigil. He has a combined health of 145,000 (217,500 in Expert Mode), the most health of any boss in the game. He is considered to be the most difficult boss in the game.
The Moon Lord has two hands and a head which must be killed by attacking the eyes on them, and when killed will release invincible True Eyes of Cthulhu. When the three eyes are destroyed the Moon Lord’s core opens up on his chest, which must then be destroyed to defeat the boss.
The Moon Lord’s hands shoot two projectiles at once which home onto the player, and summon phantom versions of the True Eye of Cthulhu and throwing them at the player. The Moon Lord’s top eye will occasionally fire a Phantasmal Deathray that will sweep across the entire screen. Being very deadly to players, it can be avoided by hiding under solid blocks or by trying to escape its wrath on a flying mount. When the True Eyes of Cthulhu are released, the places where they used to be will inflict minor contact damage. The True Eyes of Cthulhu will fire many of the same attacks as they did when they were still enclosed within the Moon Lord, but be a little less damaging. In Expert mode, the Moonlord’s Phantasmal Death Ray attack deals a lot more damage, which is enough to kill a player in one shot.