Captured by clerics of the Raven Queen, will-o-wisps are turned into lanterns that assure the dying dies and the living lives. Just be careful not to break them...

At will, you can use a bonus action to cause this lantern to shed bright light in a 5-20 foot radius and dim light for an additional number of feet equal to chosen radius. 

Consume Life. As an action, you can target one creature you can see within 5 feet of you that has 0 hit points and is still alive or died less than a minute ago. The target must succeed on a DC 10 CON saving throw against this magic or die. If the target has died or is already dead, you regain 3D6 hit points. Once used, you cannot use this feature again until you finish a long rest.