The origin probably goes back to the first anime I watched, for some reason, I liked the idea of empty eyes to represent mind control. It wasn’t really sexual until I came across the Hypno creepypasta. In one of the many videos analyzing it, there was a somewhat suggestive image alongside a phrase that clicked with me: “It’s weird for a Pokémon to hypnotize you and fuck you out of nowhere.” Then I got curious and you can imagine the rest.

Funny enough, I've never actually watche The Jungle Book lol, but I loved Kaa's spiral pattern when I came across it on Deviantart a loooong time ago. I probably like eye-altering hypnosis because it's a way to show that someone's mind has been taken over, since the eyes are one of the most expressive body parts.

I'm suprised at how common of an answer The Jungle Book is to this question. I, personally, never really found that scene that arousing (outside of the crazy animation on the eyes)