One easy path to take with an art sub lesson is to read a book or show a video and then have students draw their own interpretation from that.
Here is a vintage clip that I love. "Ugly Bug Ball." It is fun to watch and uplifting. Kids can watch and then proceed to draw their own ugly bug ball.
Pencils, paper, crayons and you are good to go.
I also have a lesson in my TPT shop that goes along with that but you really don't need it. It gives your sub more of a structure with a fully prepared script and lots of examples though. There are even art history references!
Ugly Bug Ball Lesson Plan
#Homeschool #Crayon #ThirdGrade #SecondGrade #Pencil