The early animation the absolutely blew me away when I saw it was the work of Bob Clampett (and John Coleman) early work for an never-produced John Carter of Mars, done in 1936:
https://youtu.be/bTAlgZlqwnQ?t=34
Speaking of Bob Clampett, I think he did a great job introducing surreal quasi-psych cartoons to the masses. Shame he wasn’t a decent workplace politician though.