Terraprisma

The Terraprisma is an aerial Hardmode post-Plantera summon weapon. It spawns a detached copy of itself that rapidly slashes and stabs at nearby enemies. It is dropped from the Empress of Light only when all damage dealt to the Empress occurs during the daytime, when she is enraged and all her attacks instantly kill the player.

Trivia

 * Although its sprite appears to be a sword, it is actually a summon weapon. This is similar to other sword lookalikes such as the Sky Fracture, which is actually a magic weapon, and the Durendal, which is actually a whip.
 * Despite their name, the summoned minions look nothing like the Enchanted Sword item or the Enchanted Sword enemy.
 * The Terraprisma has the highest base damage of all minion summon weapons despite being obtainable pre-Golem and only having a rarity of . This is most likely due to the high difficulty of fighting the Empress of Light during the day.
 * The Terraprisma is the only minion-summoning weapon that does not have the word "staff" in its name.
 * The way the sword attacks, pursues, and follows could be a reference to the Sword Familiar found in the game.
 * Since Empress of Light is based on Radiance from Hollow knight, and to obtain it you have to No-hit the boss, it could be a reference to the Radiant difficulty.