I just finished reading The Staff of Serapis, by Rick Riordan, a follow-up to his The Son of Sobek. Like its predecessor, it’s a crossover between his Percy Jackson/Heroes of Olympus and Kane Chronicles series, featuring characters from both and highlighting the similarities and differences between Greek and Egyptian mythology. While the first paired up Percy with Carter Kane, here it’s Annabeth Chase and Sadie Kane who team up to fight a monster and a god, and the two get along much better with each other than the guys did. The two girls battle the god Serapis in Rockaway, and the neighborhood’s devastation by Hurricane Sandy is mentioned. It turns out that Serapis’ return is likely the work of the magician Setne, who had appeared in the Kane books, and is mixing Greek and Egyptian magic. I’m not quite sure when these crossovers take place relative to the ongoing Heroes of Olympus series, although I’m guessing before because otherwise it’s guaranteed that Percy and Annabeth survive that adventure, and Riordan probably doesn’t want to do that. On the other hand, The Lost Hero was published two years before Hurricane Sandy, and it’s not like there’s any time between the events of that one and the upcoming The Blood of Olympus in which the two heroes could have had adventures in New York.
Serapis is an interesting figure, basically a compromise between ancient Greek and Egyptian mythology proposed by Ptolemy I. When the Greeks conquered Egypt under Alexander the Great, they wanted to come up with a god with Greek features who could also appeal to the Egyptians. Their first attempt was to use Amun, but he wasn’t all that popular in Lower Egypt. So instead they came up with a fusion of Osiris and the bull god Apis, hence the name Serapis. Actually, this fusion might have predated the Greek conquest, but it was the Greeks who gave him his recognizable form. The Egyptians frequently gave representations of their gods animal features, but the Greeks weren’t so keen on this, so instead they made Serapis look a lot like Hades. He was even sometimes depicted as accompanied by Hades’ guard dog Cerberus.
The hybrid god was worshipped not only in Egypt, but in Greece and later throughout the Roman Empire. His cult more or less died out in the late fourth century AD, when a Christian mob burned down his main temple in Alexandria.