The Bow of Sanguine Annihilation is a longbow of exquisite craftsmanship. The wood and string have a slightly reddish tint. Etched all over the weapon are tiny images of humanoid figures slitting open their bodies in various grisly ways and drowning other figures with their blood. A command phrase, "Ut benedicat tibi," is engraved on the arrow rest.
When firing this bow, the wielder is healed by 1d2 HP if a natural 20 is rolled to hit, and damaged by 1 HP if a natural 1 is rolled to hit.
Aside from the aforementioned effects, an attack made with the Bow of Sanguine Annihilation is normally treated as a regular, non-magic attack. However, if the wielder fires the bow while speaking the command phrase, its main power is activated. Such an attack costs the wielder 1d2 HP per level* (up to a maximum of 10d2) as blood bursts forth from the wielder's skin and coats the arrow as it is fired, leaving a contrail of crimson mist in the shot's wake. This shot has a +5 bonus to hit, does 1d6 damage per level of the wielder (up to a maximum of 10d6), and counts as an attack from a silver and/or magic weapon (whichever would be more advantageous to the wielder).
*This is the cost of using this ability in our Lamentations of the Fallen Lords campaign. Honestly, I would recommend making the cost of the bow's special attack at least 1d4 HP per level in a typical LotFP game in order to make players more hesitant about using it outside of absolute emergencies. Also, in our campaign this weapon is called the Bow of Blood Gout, and I did not specify to my players that a command phrase must be spoken, so I assume the bow's special attack is activated mentally.