The image is taken from an AI paper which explains how to use generative adversarial networks (i.e., GANs) to hallucinate hyper realistic-imagery. By training on hundreds of thousands of samples, the model is able to create candidates representing things like “just a normal dude holding a normal fish nothing to see here”, and then edit out the ones that are too egregious.
The reason the stuff above is so scary is actually that you can mathematically transition in the space between images. So for example, you could move between “a normal dude” and “just a normal fish” and have nightmare fish people. Or you could create a DNA root for an image which is part dog, part car, and part jellyfish. Check out the video below and the very accessible https://www.artbreeder.com/ website to see what I mean.