Hidden behind the humor, The Father of Animation, Max Fleisher's Columbia era cartoons had subtle adult and political messages all through them. I don't think there is any animation today that can even come close to those old 40's era cellie animations in thought or art. Some will disagree
Disney's Fantasia is another epic I believe adults will get more pit of than kids. Also, not for a lot of people, but there are some underground comics promoted by Last Gasp that are adult oriented not just because they are risque, but also due to provocative subject matter.