Mysterious Tablet

The Mysterious Tablet is a background object which spawns at the entrance to the Dungeon after Golem is defeated. Players cannot interact with it in any way, as it serves only as a graphical prop for the Cultists' ritual and the spawning of the Lunatic Cultist boss.

The Mysterious Tablet spawns surrounded by four initially passive Cultists, two of them being Lunatic Devotees and the others being Blue Cultist Archers. Once all four Cultists are killed, the Lunatic Cultist spawns, destroying the Tablet, and starting the boss fight.

The Mysterious Tablet will respawn (including the Cultists) after one in-game day, if the player runs away or dies during the Lunatic Cultist fight, when all four Celestial Pillars are destroyed, or when the world is closed and restarted. Restarting the world can be the fastest option to reset the Tablet and the Cultists to their original state.

Trivia

 * The Mysterious Tablet resembles the Celestial Sigil, a boss-summoning item used to summon the Moon Lord.
 * It appears to have the face of the Moon Lord on it.
 * Bees are the only enemy in Terraria that can damage the Mysterious Tablet - if bees are spawned from external sources such as mining Hive or fighting the Queen Bee and leading the bees afterward, then they are able to hurt and destroy the Tablet if they come in contact with it.
 * If the Tablet is spawned in and made vulnerable using third-party software, or attacked by Bees from mining Hive nearby, it can be seen that the hurt sound is the same as the mechanical bosses, and the death sound is an explosion.
 * If the Tablet is destroyed and the Cultists killed afterwards, the Lunatic Cultist will not spawn.

History
Mysteriöse Tafel Tablette mystérieuse 神秘碑牌