Terraprisma

The Terraprisma is a Hardmode summon weapon dropped by the Empress of Light boss.

It attacks by swinging itself towards nearby enemies, similar to how players use actual swords, by stabbing the enemy in quick succession before swinging in a circular motion.

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 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.
 * Might be a reference to the Sword Familiar from Castlevania Symphony of the Night, which had a Sword Familiar which is used in a similar manner.