Walt Disney tried to tackle Alice in Wonderland earlier than it actually happened. Most of these plans stopped in favor for Snow White. And when they resumed work on Alice in Wonderland, it was originally pitched as a hybrid of live action meets animation. He also released a short Mickey Mouse parody of Alice in Wonderland long before the movie.
It’s one of my favorites. I love the trippy way it unfolds, though I know it isn’t for everyone.