St. Malachy comes back from the dead for each conclave. Reason being, in the 12th century CE he made a prospective list of Popes that culminate two Popes from now–at the end of the world. The Catholic Encyclopedia tells us:
The most famous and best known prophecies about the popes are those attributed to St. Malachy. In 1139 he went to Rome to give an account of the affairs of his diocese to the pope, Innocent II, who promised him two palliums for the metropolitan Sees of Armagh and Cashel. While at Rome, he received (according to the AbbÈ Cucherat) the strange vision of the future wherein was unfolded before his mind the long list of illustrious pontiffs who were to rule the Church until the end of time. The same author tells us that St. Malachy gave his manuscript to Innocent II to console him in the midst of his tribulations, and that the document remained unknown in the Roman Archives until its discovery in 1590 (Cucherat, “Proph. de la succession des papes”, ch. xv). They were first published by Arnold de Wyon, and ever since there has been much discussion as to whether they are genuine predictions of St. Malachy or forgeries. The silence of 400 years on the part of so many learned authors who had written about the popes, and the silence of St. Bernard especially, who wrote the “Life of St. Malachy”, is a strong argument against their authenticity, but it is not conclusive if we adopt Cucherat’s theory that they were hidden in the Archives during those 400 years.
St. Malachy, or his ghostwriter, warns the faithful that the Pope assuming the Throne of St. Peter after the Pontiff who replaces John Paul II will be the last vicar; this perhaps, is because St. Malachy, or his ghostwriter, expects Jesus himself to reassume the helm. Again, from the Catholic Encyclopedia:
The last of these prophecies concerns the end of the world and is as follows: “In the final persecution of the Holy Roman Church there will reign Peter the Roman, who will feed his flock amid many tribulations, after which the seven-hilled city will be destroyed and the dreadful Judge will judge the people. The End.” It has been noticed concerning Petrus Romanus, who according to St. Malachy’s list is to be the last pope, that the prophecy does not say that no popes will intervene between him and his predecessor designated Gloria olivÊ. It merely says that he is to be the last, so that we may suppose as many popes as we please before “Peter the Roman”. Cornelius a Lapide refers to this prophecy in his commentary “On the Gospel of St. John” (C. xvi) and “On the Apocalypse” (cc. xvii-xx), and he endeavours to calculate according to it the remaining years of time.
Of course, we of scientific bearing must consider St. Malachy’s rantings as nonsense, superstition or forgeries.