_The Leyden papyrus: an Egyptian Magical Book_, by Francis Llewellyn Griffith, F.
Griffith, Herbert Thompson, page 13:|
"The use of hieratic might be thought to indicate some antiquity where it
occurs. But the writing is a strange jumble; the hieratic is inextricably
through sparingly mixed with the demotic, a single word being often written
partly in hieratic, partly in demotic, a single word being often written
partly in hieratic, partly in demotic. Where hieratic signs occur the
language is not generally more archaic than when the demotic is pure."
I found a drawing of this donkey-headed Set in The Greek Magical Papyri in Translation edited by Hans Dieter Betz, along with a translation of the spell:
It is in PGM XII. 449-52, which is a "spell of separation", in which the goal is to "Separate NN, born of NN, from NN, born of NN!" (page 170)
An interesting passage from the Leiden Papyrus:
"Soul of souls, Bull of the night, bull (?) of bulls,
son of Nut, open to me, I am the Opener of earth, that came forth from Geb, Hail!"
(One of Set's titles is 'Son of Nut', and he is often called 'Bull', as in 'Bull of Ombos')