Arm of Bloomed Strength

Your arm has been replaced! Where there was once human skin, bone, and blood, there is now a smooth obsidian black appendage, uniform except for vines of dark veins that pulsate up the arm until your shoulder. This qualifies as a magical limb and cannot be removed by non magical means.

Your Unarmed Strikes now deal an additional 1d8 Necrotic Damage when using this arm and can be made at range (15ft). This stretching effect also applies to reaching or any other uses you can think of.

However, at the beginning of each day, you must succeed a WIS save of 11 or higher, or the arm attacks a creature at random as the arm hungers. This effect can be negated daily by willingly attacking a creature, hostile or otherwise.