Isis Restores Osiris
Isis (with the help of Nephthys) searched for the scattered pieces of Osiris's body. She found all the pieces except the genitals (which had been eaten by a fish in the Nile). She reassembled the body, used her magic to restore Osiris to life, and through their union conceived Horus [S3]S3 · Plutarch, On Isis and Osirisc. 79 CEtextOpen source ↗[S4]S4 · Hornung, 'The Ancient Egyptian Books of the Dead' / 'Nile Religion' (academic)modern (translation & scholarship)academic. Anubis mummified the body, making Osiris the first mummy [S3]S3 · Plutarch, On Isis and Osirisc. 79 CEtextOpen source ↗[S4]S4 · Hornung, 'The Ancient Egyptian Books of the Dead' / 'Nile Religion' (academic)modern (translation & scholarship)academic.
Ancient Egyptian religion spanned three millennia. There is no single 'official' version: Heliopolitan, Memphite, and Hermopolitan creation traditions coexisted and are presented in parallel, not merged into a genealogy that never existed.
The 'lost genitals' detail is a later (Greco-Roman) addition [S3]S3 · Plutarch, On Isis and Osirisc. 79 CEtextOpen source ↗[S4]S4 · Hornung, 'The Ancient Egyptian Books of the Dead' / 'Nile Religion' (academic)modern (translation & scholarship)academic.