What is the name of Odin's golden ring that multiplies itself?

Odin’s golden ring that multiplies itself is called Draupnir.

In Norse mythology, Draupnir is a gold ring whose name is usually translated as “the dripper.” Every ninth night, eight new rings drip from it, and each is the same size and weight as the original. This supernatural multiplication makes Draupnir both a symbol of abundance and one of Odin’s notable treasures.

The ring was forged by the dwarf brothers Brokkr and Eitri, also called Sindri in some traditions. It was created during a contest involving gifts for the gods, alongside Thor’s hammer Mjölnir and Freyr’s boar Gullinbursti. Loki had wagered that the dwarfs could not surpass the work of another group of craftsmen, but their gifts proved extraordinary.

Draupnir plays an important role in the story of Baldr’s death. Odin places it on his son’s funeral pyre, and Hermóðr later retrieves it from the realm of the dead. It is not Mjölnir, Thor’s hammer, or Gungnir, Odin’s spear. Brisingamen is instead the famous necklace associated with Freyja.