Der Ring des Nibelungen
Wagner made a lot of changes to the story in order to make it suitable for his four operas.  Wagner’s story tells of a hoard of gold which is being guarded by the Rhinemaidens.  The dwarf Alberich steals the gold and uses some of it to make a ring which makes the owner powerful over all the world.  When Wotan, the chief god, steals it from him, Alberich puts a curse on the ring.  The ring will bring death to whoever has it.  The ring goes through the hands of several characters, all of whom die in the end.