Icemourne

This weapon is currently not actually included in the game. Attempting to obtain through the use of an inventory editor will result in the item becoming an angel statue. It is not currently known why this weapon was removed. According to the tooltip, it does the same damage as the Adamantite Sword.

Trivia

 * This sword's name and appearance is a reference to Arthas's weapon, Frostmourne, from the Warcraft franchise. This may be a reason for removing it.
 * As of 1.2.3, the Icemourne can in fact be obtained. The weapon's name, sprite, and overhead swinging animation work, however, the weapon has no statistics, thus attempting to use it as an actual weapon will not affect the enemy you are trying to attack.