Silver Hand of Nuada

The Silver Hand of Nuada was an Irish Celt artifact reputed to grant its wearer immortality.

History
According to legend, the Silver Hand was created by Diancecht as a replacement for the limb lost by Nuada, the future king of Ireland, during the Tuatha de Danaan's battles against the Fir Bolg on the Plain of Moytura in modern-day County Mayo. A 15cm long, seven kilogram silver replica of a human right hand, the prosthesis allowed Nuada to rejoin the fight and claim victory. Nuada's real hand was eventually restored and the Silver Hand later disappeared when Nuada fell during his clash against the Fomorians.

The Silver Hand somehow found its way to Great Britain where it lay in the ruins of a pre-Christian temple beneath St. Paul's Cathedral, London (although it was also believed to secreted away within a chamber beneath the Stone of Scone at Westminster Abbey). Rumor held that Nuada still guarded his Silver Hand and protected it from those who weren't followers of the old gods.

In the early 1930s, an unknown archaeologist working for the Smithsonian cataloged the Silver Hand of Nuada as part of their research into the world's artifacts.

The Silver Hand was of interest to a number of parties, including Adolf Hitler himself who sent German agents in search of the artifact. A group calling itself the Order of the Tuatha de Danaan sought the hand as part of its machinations to revive the old gods while the Royal Anthropological Society simply felt that the hand was of used to validate to the stories of Nuada and the Tuatha de Danaan.

Powers and physical makeup
Despite its rumored promises of immortality, the Silver Hand of Nuada would only function if attached to a severed wrist, allowing its wielder to move the hand as their own after an hour, and granted them physical prowess and fighting skills comparable to Nuada. However, the hand would enact its cost from the second day, draining its owner unless severed which even then risked damage the wielder.

Behind the scenes
Described in the text of Indiana Jones Artifacts as a right hand, the picture accompanying the Silver Hand actually depicts that of a left hand.