This is stupid. He IS too big, relative to his spatial positioning. None of the other humans are 5 grid squares tall. Don't think you can rightly call it an optical illusion if it's a manipulated photograph like this.... That's just your eye telling you something isn't right with perspective and scale.
One of the early designs of the guillotine, on diminutive garden pests. It was later scaled up to human size, as it was discovered that humans were much easier to catch.
It's a visual element used for dramatic effect, used in art or food displays; a fountain. Suggested accompaniments include melted chocolate, caramel, or any other tasty gooey substance.
Hip Hip Array, XXL
Hip Hip Array, 2XL
["hip", "hip"], xxl