Drow crossbow bolts are coated with poison. The victim of a successful attack must succeed on a DC 12 Constitution check or fall unconscious within 1d6 rounds for a duration of 1d6 minutes.

On the first round of combat, if the environment allows the creature to hide, the target must succeed on a Wisdom check (DC [15 + Dexterity modifier]) or be Surprised. If it successfully attacks a surprised target, the creature deals +1d6 damage and any creature with lower Strength than its own is Knocked Prone. The creature gains a +5 bonus to all Stealth checks and to Initiative.