House of Secrets #59 (1963)

A man named Jason Bradford visits his doctor and finds that he has six months to live. He wanders into a bookstore where he finds a book about the Legends of the Pharaohs Feast. The story describes the tale of an ancient dying pharaoh who invites 12 nobles to a farewell feast. The pharaoh then hears of a magician named Zaljaz who has the ability to grant the gift of immortality to anyone. The magician is summoned before the pharaoh. He informs the pharaoh that Nuri, the cat of eternity will leap to his shoulder and grant immortality if he can simply juggle three silver balls. The weak pharaoh attempts to juggle the balls but they fly off everywhere when thrown in the air. The pharaoh dies succumbing to his illness. Bradford continues reading and learns that Zaljaz appeared throughout history as the 13th guest to challenge others to juggle the balls but they all met with failure. Bradford decides to throw a party and invites 12 of his closest friends. He hopes to outwit the magician if he can make him appear. The night of the party arrives and the 12 guests show up for Bradford's feast. The ancient magician suddenly appears with Nuri the cat on his shoulder. Bradford then asks to take the challenge and to everyone's surprise he is easily able to juggle the silver balls. Bradford had cleverly implanted magnets into his walls to make the balls more controllable. Zaljaz knows that he has been tricked somehow but he has no choice but to let the cat Nuri jump to Bradford's side. The disgruntled magician then uses his magical power to send Bradford and his guests to ancient Pompeii on the night that the volcano erupted. Bradford realizes that his friends will be killed so he has not choice but to surrender the black cat of immortality back to Zaljaz. The magician then sends everyone back to the safety of the present and Bradford realizes that he will still die in six months. Upon visiting his doctor, Bradford learns that his disease is completely gone. The doctor surmises that a scratch on his shoulder has introduced antibodies into his bloodstream destroying the deadly germs in his body. Bradford realizes that the scratch came from Zuri the black cat and he refers to it as the Scratch of Immortality.