In Norse mythology, Andvari, whose name means "careful one" in Old Norse, is a dwarf residing beneath a waterfall. He possesses the ability to transform into a pike (gedda) whenever he wishes.
Andvari possessed a magical ring known as Andvaranaut, which bestowed wealth upon him. Loki, with the help of a net provided by Ran, captures Andvari in his pike form and coerces him into relinquishing his gold and Andvaranaut. Andvari placed a curse on the stolen gold, proclaiming that it would bring ruin to anyone who possessed it. After the deaths of Brynhild and Sigurd, Gunnar left Andvari's gold in a cave. Many years later, Andvari rediscovered the cave and his lost gold, although his ring was lost forever.
In Richard Wagner's series of music dramas, Der Ring des Nibelungen, the character Alberich is a fusion of Andvari and the character Alberich from the Nibelungenlied.
.