A carfoon is a drawing brought to life using magical paints.
A carfoonist uses magic-infused paints and inks to bring drawings to life, but not everyone can create them because it requires study and training.
Carfoonists are required to study all the arts to understand life before they can bring carfoons to life, and their works used to live on forever. But a legend says that an angry student once dabbled in dark art and accidentally created the Dark Lord, so paints are now regulated so carfoons can live for only three weeks.
Charles Schmutz offered to teach Arnie some rudimentary carfooning magic at 65 coins per hour. Although we don't know if Arnie took up his offer, he did end up trying some cartoons of his own, as did Usidore and Chunt. They seemed to gain some proficiency at it.
Notes
According to professional carfoonist Charles Schmutz, carfooning is one of the twelve arts of Foon.