Seal of Solomon
So there's a story about the ancient King Solomon. He was tricked by the demon Asmodeus, who spat him six and a half kilometres outside his kingdom and pegged his magic demon-subduing ring into the ocean. Then the demon pinched the throne for himself. After bumming around a while, falling in love with an Ammonite princess, and getting the two of them exiled to the desert somewhere, Solomon bought a fish and found the bloody ring in its guts! What are the chances? So old mate goes back to his kingdom and flashes the ring around to prove he's legit, and Asmodeus conveniently buggers off without a fight.