Vorpal Sword (Longsword) 2014
Weapon, legendary, (requires attunement)
You gain a +3 bonus to attack and damage rolls made with this magic weapon. In addition, the weapon ignores resistance to slashing damage.
When you attack a creature that has at least one head with this weapon and roll a 20 on the attack roll, you cut off one of the creature's heads. The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to slashing damage, doesn't have or need a head, has legendary actions, or the GM decides that the creature is too big for its head to be cut off with this weapon. Such a creature instead takes an extra 6d8 slashing damage from the hit.
Properties
Versatile (1d10)
This weapon can be used with one or two hands. A damage value in parentheses appears with the property—the damage when the weapon is used with two hands to make a melee attack.
Other versions
Source: System Reference Document 5.1 (Wizards of the Coast) · License: Creative Commons Attribution 4.0 / OPEN GAME LICENSE Version 1.0a details