Frostbrand

Hardmode Sword. Drops from Ice Mimics found in Underground Snow biomes. Besides its use as a regular sword, it fires an icy projectile towards the mouse pointer when swung. This projectile emits a fair amount of light, is not affected by gravity, deals the same amount of damage as the sword itself, and can pierce through a single enemy. This ability costs no mana, but has a small cooldown. This sword could be considered to be an upgrade to the Ice Blade, due to its similar functionality and effects.

The Frostbrand is a rather powerful Hardmode sword, even when compared to the Excalibur: the former has slightly higher base damage, added ranged capabilities, is far easier to obtain (since no Hardmode bosses have to be defeated), only lacking in the continuous swing capabilities of the latter.

Trivia

 * This item is a reference to Nethack, a classic computer Roguelike in which it was one of the strongest weapons in the game.