Animation - Transparency

Animation done for a college semester project. I was given the prompt "Suddenly, I found myself in a mysterious place. I looked around me, but there was nothing. As time passed, I began to feel the disturbing sensation of being watched. Suddenly, a fright made me disappear. Now I understand that... Maybe the ghost was me?" and was tasked for producing a 2D animation based upon that. Also it should have a background and I needed to produce a thumbnaill for a scene, indicating which principles I was able to identify in said movement