Troll Slayer Arrow

Arrow +2 of troll slaying When shot against a troll or other regenerating creatures: the creature must pass a save or die. Pass: the arrow do normal damage +2 Fail: the arrow merge with the creature blood and grow into a wondrous flower.  Roll 1d6 to determine the nature of the flower: Carnivorous flower hungry for more blood. HD as 1/2 target HD, dmg 1d6 biting damage + blood