Transcription
A drawing of a naked person being dragged away by a green demon; the drawing is surrounded by a border with various drawn mussels and clams. The caption reads “Monk 1: What are you drawing? Monk 2: A poor soul being dragged to hell by demons. Monk 1: Cool! And what are you planning to use as a border? Monk 2: I’m thinking freshwater mussels. Monk 1: That’s really perfect.”


Middle-ages cloistered monks really had a lot of time on their hands and no other entertainment, so yeah, crazy art of whatever comes to mind.
I think the period that this book was illuminated in was from later when really fancy books was more of a business for the church. Usually the very early illuminated books were made by a single monk doing most steps of the process (prepping parchment, calligraphy, painting, binding, etc.) but the later books like this may have had different artists for the illuminated letters vs the borders. So there could have been one monk that just likes sea stuff and he was too good for the other brothers to tell him to stop.
Source: mostly vibes, but I’ve dipped my toes into illumination and guilding
Weren’t they also often chained to the desks to meet their deadlines tbf?
The first thing that comes up on a websearch is books being chained to desks, to keep them from getting borrowed. I can’t imagine monks chained to their desks will be motivated to do good work, let alone fine art like illumination. Especially if they’re under a deadline, which would serve to propagate errors and misspellings.