I've been playing with ideas for layered animations using the DoInk Animation iPad app. One idea is to split up the natural layers in a photo and add animated layers in between. I used a spooky house photo and began by importing it into a drawing app where I could color, blend, and mask out the tree in the foreground. Then I imported the original photo into Superimpose app to isolate it and save it as a png with a transparent background. See how here.
This idea is a completely drawn animation. Students would need to prepare each layer of the composition as separate drawings in the DoInk app first. Below are the layers I drew. Some are stagnant: cloud, tree, and the sky/moon. Some have "flip book" styled animation where I change something to make the drawing move. This is found in the ghost, bat, and the flashing eyes of the house.
Learn about MultiPlane Animation
See this post for resources to teach the lesson.
Here is another version of a spooky layered animation. This time I made a painting in the museum haunted with a semi-transparent ghost flying between the layers. The animation (made in DoInk Animation app) was loaded behind an empty picture frame using the DoInk green app.