It's not clear what field he's in, but Korean professor Cho Yul has studied "experimental works [involving] reflection, refraction and shadow for about 30 years." Around four years ago he designed a cup lined with reflective strips and a saucer containing some very deliberate marks, which yields this effect:

Together with son Cho Sang Ha, Professor Cho has launched Luycho, a company that sells the cups in a variety of designs. Interestingly, depending on the size of the animal/animation, some require saucers with off-center depressions for the cup:

Sadly, the Chos made the mistake of releasing a video of their invention before they were ready to go to market. As you can expect these days, this happened:

"In the course of the research, a brief video clip released on Instagram has attracted interest and attention from many customers, but it also provided the basis for the crude fake goods to be distributed on the market first.

"Nevertheless, we have invested the period of four years in silence, as we needed a very delicate task for the product to come out. As a result, we succeeded in making the horse run vigorously in the actual product. The imitation products just imitate the video of early works, the horse doesn't run actually.

"What is being sold in Amazon are not Luycho. Please be advised. For those who are coming from the US, please purchase our products from the certified stores available on the profile page."