Astaroth's hand of death

A spell created by the demon Astaroth. a spectral hand made of the flesh of his slain enemies. if the hand touches a living person they take 2d8 necrotic damage. if reduced to 0 hit points, the creature/character/npc roles a d20. on a 10-5, the creature/character/npc is turned into an undead, who has to obey the caster's commands.