The original cover of The Hobbit has runes running along the outside; the runes read "The Hobbit or There and Back Again, being the record of a journey by Bilbo Baggins of Hobbiton compiled from his memoirs by JRR Tolkein and published by G?rge Allen and Unwin Ltd"[0].
I can read that because of my mum's books on doing fortune telling with Viking rune stones, which she kept near her statue of a Hindu god and some magic crystals.
At this point, calling one of the sacraments by a silly name is the least of my problems if it turns out to all be real.
(Knowing what an inscription means is actually an important real-world method of being able to read it!)
The "Z" used by Tolkien there appears to be his own invention. The whole inscription is something of a mess; a few things are put into runes by sound, but mostly a fairly strict letter-to-letter transcription is used. This is especially bad in "published", which prints an "S" followed by an "H", reflecting nothing about the actual word. (The sound in question would, in a real Anglo-Saxon text, be represented sc, not sh; Tolkien in his other documents used a mirror-reversed S rune instead.)
Only when they have gathered for the ritual at the annointed hour, when the cleric speaks the incantation does the transubstantiation occur, that they may feast upon the flesh and blood of their god.
I'm sure you've just committed some named, historical heresy. There's one for everything, it seems.