Lunatic Cultist

The Lunatic Cultist is a Hardmode, post-Golem boss summoned by killing all four Cultists that spawn at the Dungeon's entrance after Golem is defeated. Beating the Lunatic Cultist initiates the Lunar Events.

Behavior
The boss only has one defined stage, but its attacks become progressively stronger as it loses health. During the fight, it can fly and usually stops above the player when it changes position. It has multiple attacks including lightning, fireballs, shadowflames, exploding packed ice, and two volleys of five destructible stardust projectiles each.

It will often project illusory duplicates of itself, only one of which can be attacked to deplete the boss's health. These illusions can be prevented by damaging the Cultist enough while it summons them(damaging the clones during this process also kills them off). The illusions are semi-transparent, As well as have bigger 'eyes', which makes it easier to tell them apart.

Each time the player attempts to attack one of these illusions, the Lunatic Cultist summons a Phantasm Dragon, a Wyvern-like enemy, to attack the player. If the Phantasm Dragon is not defeated and the player attacks another duplicate, an Ancient Vision, which looks like the head of the Moon Lord, will be summoned. The Phantom Cultists have a error: It says Luantic Cultist instead of Phantom Cultist.

Tips

 * Avoid defeating the Lunatic Cultist if you are not yet ready for the Lunar Events, as after beating the Cultist the Lunar Events begin immediately, and there is no way to de-summon them (aside from defeating them). Take care that any minions/NPC's in the area don't kill the cultist in defending you/themselves.
 * Shooting the decoy cultist is not a bad idea if you have vampire knives. The Phantasm Dragon is very long and you can easily regain some life by hitting the Dragon with a wide barrage of knives.

Trivia

 * It appears visually similar and may be a nod to Crowno, an artist at Re-Logic, whose vanity set is often the subject of discussion and speculation by fans. It, as well as the Lunatic Cultist's graphics, resemble a plague doctor costume, which was a garment worn by physicians who treated the Black Plague in 14th century Europe.
 * Another reason why this might be a nod to Crowno is because in the trivia section of Moon Lord, someone has posted, "Terraria's final boss was originally going to be the Moon itself descending on the world, but Cenx later stated that this idea had been abandoned in favor of a new, unknown concept proposed by Crowno." All these events are partially connected, hinting the whole Lunar "scenario" might be courtesy of one of the one and only, Crowno.
 * It is the smallest boss, and the only boss without an awakening message, and the only character in the game that speaks (it says "How do you know" when summoned).
 * The word lunatic comes from the Latin luna, because it was believed that people were more likely to exhibit aberrant behavior during a full moon. This may explain why the Lunatic Cultist takes a part in the summoning of the Lunar Events.

History
Cultiste Lunatique