When you attack a creature with this magic weapon and roll a 20 on the attack roll, that target takes an extra 10 necrotic damage if it isn't a construct or an undead. You also gain 10 temporary hit points.
Note: According to the SRD, it is an extra 3d6 necrotic damage, although this is incorrect.
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.
When you attack a creature with this magic weapon and roll a 20 on the d20 for the attack roll, that target takes an extra 15 Necrotic damage if it isn't a Construct or an Undead, and you gain Temporary Hit Points equal to the amount of Necrotic damage taken.
A Versatile weapon can be used with one or two hands. A damage value in parentheses appears with the property. The weapon deals that damage when used with two hands to make a melee attack.
If you hit a creature with this weapon, that creature has Disadvantage on its next attack roll before the start of your next turn.