Hi! The way you've described it doesn't bring a particular, popular or historic way of working to mind. But you've described a way of approaching art that can certainly be called intuitive drawing, or drawing from the subconscious. As a longtime art teacher I can tell you that many art teachers, especially in high school and middle school, have their students do exercises like this to loosen up and to turn off the part of your brain that is critical of what we draw. Many teachers over the years have made up their own name for that type of project, mainly out of necessity because we need a "name" for each project in the grade book. If I made this assignment tomorrow I'd call it Intuitive Drawing from your Subconscious, or Doodle For Inspiration, or something like that, depending on the age of my students and the tone of the class.
If you're interested in learning about other freewheeling art exercises from history, you'd like reading about "Exquisite Corpse" and about artist Jean Arp's "Composition Arranged According to the Laws of Chance."