Great fan project! Kennywdev made a prism of acrylic glass and mounted a camera on top for image tracking. Then, he projected some 3D Pokémon scenes that he made in Unity on it. It's a very smart way to create cool-looking holographic projections. It's worth watching a tutorial on how these are made, it's actually not that difficult.
Here's video of the final results:
And some WIP pics. Very cool!