Treebane

The axe's handle is carved with leaves and vines, and it weighs half as much as a normal battleaxe. When the axe hits a plant, whether an ordinary plant or a plant creature, the target takes an extra 1d8 slashing damage. When a creature of non-good alignment wields the axe, it sprouts thorns whenever its wielder makes an attack with it. These thorns prick the wielder for 1 piercing damage after the attack is made, and this damage is considered magical.

Versatile: This weapon can be used with one or two hands. A damage value in parentheses appears with the property—the damage when the weapon is used with two hands to make a melee attack.

Proficiency: martial, battleaxe Source: Curse of Strahd p. 198