Glimmer experienced trauma after her mother's death suddenly forced her from the pink, sparkly, rebellious Princess of Bright Moon to its Queen, and she had no opportunity to address that in a heathy, supportive environment.

Source: https://collider.com/fictional-queens-we-love/

“This crawler captured the attention of the world during the Artemis I mission when it carried the rocket and spacecraft that will send our astronauts to the Moon to the launch pad.”

Source: https://gizmodo.com/nasa-massive-rocket-transporter-world-record-artemis-1850282480

Though it is not explicitly stated what happened to cause Mr. Moon to be so scared of the quiet creatures, it is unusual for someone to be so afraid of them to cause a Boggart to transform into one.

Source: https://screenrant.com/hogwarts-legacy-demiguise-statue-locations-man-behind-moons/

With the arrival of a Last Quarter Moon to start the week it’s a good time to go stargazing, planet-spotting and comet-hunting.

Source: https://www.forbes.com/sites/jamiecartereurope/2023/02/12/see-venus-shine-close-to-neptune-as-skies-darken-the-night-sky-this-week/