Mahoney??? Sorry, I just can't abide that man.
Funny that Malachy's prophecy for Peter the Roman says NOTHING like that at all. It says:
"In persecutione extrema S.R.E. sedebit Petrus Romanus, qui pascet oves in multis tribulationibus: quibus transactis civitas septicollis diruetur, & Judex tremêdus judicabit populum suum. Finis. (In extreme persecution, the seat of the Holy Roman Church will be occupied by Peter the Roman, who will feed the sheep through many tribulations, at the term of which the city of seven hills will be destroyed, and the formidable Judge will judge his people. The End.)"
Nothing about Satan being pope.