Eyes/pairs of eyes(not yet decided) will float in darkness and sing together a (creepy) bedtime tune(a capella), which can be different depending on the combination the user chooses with the fingers. Each eye will have its own specific voice/part. They will also make sounds every time they hit one another (first second of their specific sound, let’s say). Will float, but can be dragged by the user (or pressed and kept in place); whenever they are pressed, they will start the tune.
Maybe it could have a simple music box loop playing in the background all the time, or more probably some ambience.
It’s quite difficult to explain my idea using graphics, but basically this is how the app should look like:
Oh, and the (main) inspiration source: