The Beam Sword is a Hardmode weapon dropped by Armored Skeletons. This weapon has the ability to shoot a damaging yellow beam of light alongside normal attacks. This beam can be fired on a cooldown of roughly one second, during which the player cannot select another weapon to use.
When a beam of light is ready to be fired, the "full mana" sound and particle effect will occur.
The Beam Sword is in the same weapon family as and can be considered a weaker version of the Terra Blade, True Excalibur, and True Night's Edge due to its higher cooldown time, lower damage and speed, and smaller size.
The best prefix that can be obtained with this weapon is "Legendary."
The speed of the flying beam is affected by attack speed.
It is recommended to use this sword if you're lucky enough to have it drop at the start of Hardmode as it has a higher base damage than the swords crafted from any of the Hardmode metals (except for Chlorophyte) up to and including the Excalibur.
Beam shooting swords are commonly seen in many fantasy games, Legend of Zelda as example.