I was playing around with the Spine runtime for the Godot engine and used it to make a Painting that looks at the player, similar to the mixing animations demo with the owl. The effect is pretty subtle though.
Spooky Portrait with Spine-Godot
It's really cool, though I had to watch twice to get it since it's subtle and the video is dark. However I think it being subtle adds to the creepiness! I'd only be worried that players miss it.
Ooh! I had to look at it twice too, as it is indeed so subtle one could miss it as a perspective trick of the eye, nice!
Sweet!
Really cool!