Terraprisma

The Terraprisma is a Hardmode summon weapon dropped by the Empress of Light boss. The weapon will only drop if 100% of the damage dealt to the Empress occurs during the daytime, when she is enraged.

When used by a player, it creates a detached copy of itself and autonomously attacks by swinging and stabbing at nearby enemies. Each instance counts towards the standard minion cap.

Trivia

 * Although its sprite appears to be a Sword, it is actually a Summoning Weapon. This is similar to the Sky Fracture, which looks like a sword but is a Magic weapon.
 * It will only be dropped by the Empress of Light if she is entirely damaged and killed during the day, when her attacks do increased damage. If any damage is done to her at night, the Terraprisma will not drop.
 * Despite the weapon's tooltip, the summoned minions look neither like the Enchanted Sword item or the Enchanted Sword enemy.
 * The Terraprisma has the highest base damage of all minion summon weapons, despite being a drop from the Empress of Light, a post-Plantera boss, and having a rarity of.