If you stare at a pattern where the horizontal stripes are red and the vertical stripes are green, you might forever see horizontal & vertical stripes as having color even when they don't.

https://en.wikipedia.org/wiki/McCollough_effect

Sheperd tones. Sounds that appear to either rise or fall forever https://youtu.be/sjCLyi8bdBA

Uncanny Valley: https://en.wikipedia.org/wiki/Uncanny_valley

tl;dr: Neither regular, boring, human faces nor highly stylized comic / chibi / animated human beings are percieved as "inhuman", but as soon as an artificial face looks too real but still slightly off, basically the middle of the scale between "real" and "definitely man-made", it can provoke feelings of extreme discomfort in the viewer. You're basically creeped out by something that tries to look human but fails at that only barely enough to notice.

I am a big fan of the McGurk effect: https://youtu.be/2k8fHR9jKVM

Creating the feeling of body ownership. Trippy and makes me jump every time.

https://m.youtube.com/watch?v=lYQLFl-hgts

https://en.m.wikipedia.org/wiki/List_of_cognitive_biases