When you roll a 20 with this magic weapon, the target takes an extra 7 Piercing damage.
Note: According to the SRD, it is an extra 2d6 Piercing damage, although this is incorrect.
If a weapon has the thrown property, you can throw the weapon to make a ranged attack. If the weapon is a melee weapon, you use the same ability modifier for that attack roll and damage roll that you would use for a melee attack with the weapon. For example, if you throw a handaxe, you use your Strength, but if you throw a dagger, you can use either your Strength or your Dexterity, since the dagger has the finesse property.
This magic weapon deals an extra 2d6 damage to any creature it hits. This extra damage is of the same type as the weapon's normal damage.
If a weapon has the Thrown property, you can throw the weapon to make a ranged attack, and you can draw that weapon as part of the attack. If the weapon is a Melee weapon, use the same ability modifier for the attack and damage rolls that you use for a melee attack with that weapon.
If you hit a creature with this weapon and deal damage to it, you can reduce its Speed by 10 feet until the start of your next turn. If the creature is hit more than once by weapons that have this property, the Speed reduction doesn't exceed 10 feet.