Close Wounds

Your ally falls from a crushing blow, but you don't have time to reach him. You quickly speak words of power, and the worst of his injuries glow golden and begin to heal.

When cast, Close Wounds, allows the player it is cast upon to use one of their hit dice plus the casting modifier of the caster to heal themselves.  This spel can only be used on a character once per long rest.

If you cast this spell immediately after the subject takes damage, it effectively prevents the damage. It would keep alive someone who had just dropped to —10 hit points, for example, leaving the character at negative hit points but stable.

Used against an undead creature, close wounds deals damage instead of curing the creature (which takes half damage if it makes a Will saving throw)