Moon Lord

The Moon Lord is a boss that is battled after all four Lunar Events (vertex pillars) have been defeated, serving as a "final boss" to the game.

When fighting the Moon Lord take caution as he shoots out True Eyes of Cthulhu serving as hazards shooting lasers at the player. Much like Skeletron the Moon Lord has two hands and a head, though unlike Skeletron the head does not charge at you nor do the hands.

Some of his main drops include the Portal Gun,the Meowmere, the S.D.M.G., the Rainbow Crystal Staff, the Last Prism, Star Wrath, the Lunar portal staff, the Celebration, and the Lunar Flare

Trivia

 * The Moon Lord shoots out "True Eyes of Cthulhu", hinting that the Moon Lord could be Cthulhu, however this is unlikely as it was confirmed that Cthulhu would not be in 1.3.
 * The boss was originally planned to be the moon itself descending on the world, however Cenx later stated this plan had been abandoned in favor of a different concept, presumably the Lunar Events.
 * This old concept could possibly be a reference to The Legend of Zelda: Majora's Mask.