This book seems a little dark for a children’s book. The mice prepare for there first Mardi Gras and make masks that look like monsters and forget they are mice and become the monsters.
It seems the author is really either voicing his opinion of Mardi Gras or just thought of being careful not to lose yourself in something bad or I suppose both those things.
Why it is called the Greentail Mouse is because one of the mice tail gets paint on it and it never can remove the paint. A reminder that even if they forget that they were monsters once and to not to return to that way of being.
I think it is a good message in general I don’t know if it has to be applied to Mardi Gras as I have never participated in the event but I can see how it fits.