Umbral Chopper

This simple axe looks no different from a standard forester's tool. A single-edged head is set into a slot in the haft and bound with strong cord. The axe was found by a timber-hauling crew who disappeared into the shadows of a cave deep in an old forest. Retrieved in the dark of the cave, the axe was found to possess disturbing magical properties. You gain a +1 bonus to attack and damage rolls made with this weapon, which deals necrotic damage instead of slashing damage. When you hit a plant creature with an attack using this weapon, the target must make a DC 15 Constitution saving throw. On a failure, the creature takes 4d6 necrotic damage and its speed is halved until the end of its next turn. On a success, the creature takes half the damage and its speed isn't reduced.