In
The Glories of Mary, (Pt. I, ch. vii., art. 1, trans. Rev. Fr. Eugene Grimm; New York: Benziger Brothers, 1887), Saint Alphonsus relates this curious account of a demonic monkey and how an otherwise reprobate worldling was saved from the snares of satan by perseverance in his daily devotions to Our Lady.
This example was expunged from later editions of the celebrated tome of St. Alphonsus published by Benziger Brothers and replaced with another example related by the Saint in some other work. I presume it was because readers tend to get the wrong impression that Our Lady will save sinners if they merely say some prayers to her.
However, such interventions as related below are exceptional, and they serve to illustrate in a spectacular and convincing manner (so that even the infidels may not have reason to doubt) the immeasurable power and clemency that the Blessed Virgin shows to those who either recommend themselves to her or have been recommended to her by others (parents, kin, friends, Priests, etc.). She will ultimately exercise her great authority as Mediatress of all graces won by her Divine Son, and shall grant the grace of final perseverance to those who cooperate with holy grace and thereby give themselves over to prayer, self-abnegation, interior and exterior mortification, good works, &c.
Lesson to be learned: ever persevere in your morning and evening devotions, and in your accustomed prayers to Our Lady, 'cos you never know when a satanic monkey shall suddenly haunt round about you, seeking to hurl your soul down even unto the depths of hell.