First off, sorry for the bad framerate, my PC is pretty bad.
Anyways, in the E3 Demo, Cerberus (the 14th colossus) has a function that allows it to move its eyes around, following Wander's location. In addition to that however, there is a hidden feature within, that being animations and scripts for eyelids (named "mabuta").
Everything is already set up in-game, but they do not apepar as the models were replaced with flat transparent squares, rendering them invisible. The only thing I did was create the model of the top part of the eyelids and that's it. The game automatically duplicates and mirrors it to the bottom, creating a second one underneath.
The animation for the eyes, named "objanim_cerberus_eye.anb", is set to repeat itself indefinitely. All it does is close the top and bottom eyelid (blink).