Terraprisma

The Terraprisma is an aerial melee Hardmode post-Plantera summon weapon dropped by the Empress of Light. The weapon will only drop if 100% of the damage dealt to the Empress occurs during the daytime, when she is enraged (where all the attacks kill the player instantly).

When used by a player, it creates a detached copy of itself and autonomously attacks by stabbing and swinging at nearby enemies

Tips

 * A good strategy for defeating the Empress of Light during the daytime is to build a skybridge out of Asphalt Blocks. When daytime comes, use Hermes Boots (or one of its tinkers) and Swiftness Potions to run across the skybridge at full speed while damaging the Empress with a high damage weapon. Moving at such high speeds will allow you to easily dodge her attacks while damaging her from a safe distance. A good weapon choice would be the Chain Gun or Megashark with Chlorophyte Bullets, as dodging should be your main focus during the fight rather than worrying about aiming.

Trivia

 * Although its sprite appears to be a Sword, it is actually a Summoning Weapon. This is similar to the Sky Fracture, which also looks like a sword, but is actually a Magic weapon.
 * 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, even though it is obtainable pre-Golem and only has a rarity of.
 * The Terraprisma is the only summon weapon, aside from whips and the Tavernkeep's Sentries that does not have the word 'staff' in its name.

History
Terraprisma