the festum asinorum, which, so far as I know, was celebrated mainly in France… the ass procession went right into the church… the whole congregation brayed, that is, they all went ‘Y-a’ like a donkey
Jung identifies the Feast of the Ass as evidence of the trickster’s survival in Christian liturgy, where collective braying expresses the irrepressible animal-instinctual stratum of the psyche.
, The Archetypes and the Collective Unconscious, 1959thesis