Okay, put the Spanish for “moon”, Luna, being related to Lunatic, in the category of, “It’s so obvious you never realized it until someone once pointed it out to you!”.
Nighttime has historically, since ancient times, been associated with danger and the crazy riskiness that comes alongside it. This is manifested in many forms, including the Luna/Lunatic parallel.
Think, also, about parallel English cliches like, “shooting for the moon”: someone who is trying something that is so risky and unlikely to succeed that you must be insane to even try it!
