Mingus sometimes drew a picture of a coffin rather than chords for musical direction. Erik Satie had a similarly free sense of guiding musicians.
Some of our favorite things Satie wrote under musical passages:
Light as an egg
Like a nightingale with a toothache
Wonder about yourself
Meant to mock works such as Debussy’s Preludes
Of course, there’s a charming, jazzful poetry about such directives. But – honestly – aren’t they also more helpful to the musician than “mezzo forte”?