A few years ago I drew on clear umbrellas with a similar idea:
"Why does it always rain when I am on playground duty?",
aimed squarely at the teachers in your life!
Here it is again but in a 'chalkboard' design.
It is available at my Artsadd store (just click the above image to go there)
and I thought their black umbrellas would be perfect to try out this 'chalky' design