The phrase first appears as a proper noun, the stage name of a renowned English magician of James I's reign, whose patter ran something like hocus pocus, tontus talontus, vade celeriter jubeo, nonsense with one real Latin tail: go quickly, I command. His fame made the incantation generic; by 1634 the anonymous Hocus Pocus Junior: The Anatomie of Legerdemain fixed it in print. Archbishop Tillotson's rival theory, a corruption of hoc est corpus by way of ridiculous imitation of the priests' trick of Transubstantiation, has no documented historical basis, though the phonetic resemblance is real.
The Mass theory survives on plausibility: the priest faced east, back to the people, mumbling Latin without microphones; hoc est enim corpus meum, chanted with long vowels and resonant O's, sounds to the untrained ear exactly like incantation. Peasants, Puritans, and bad acoustics all get blamed for the same hearing error. The deeper point the folklorists make: sacred chant everywhere, Avestan, Sanskrit, Latin, relies on vibratory rhythm the body feels before the mind parses, which is why the mock spell needed no dictionary to work.
The claim: hocus pocus proves stage magic and sacrament share one technology, patterned vocal authority producing transformation, and the distinction between transubstantiation and a rabbit-from-hat is licensing, not mechanism; the Archbishop sensed the competition because it was real: his altar and the magician's table run the same performance grammar. Verdict: the speech-act wing agrees, performatives with and without licensed officiants. The word's three-century career is the audience voting with its laughter. Whether that laughter desecrates the altar or just recognizes the family resemblance is the question Tillotson could not settle, and the archive declines to close.
If the magic words are a mangled sacrament, who is the trick really on: the audience, or the altar?