How does the undertaker do that thing with his eyes?

The Undertaker, a professional wrestler, is known for his ability to roll his eyes back into his head, creating a dramatic and eerie effect. This technique is achieved through a combination of eye muscle control and focus. By contracting certain muscles around the eyes, he is able to move his eyeballs upwards and backwards, giving the appearance of rolled-back eyes. It is a skill that requires practice and control over the eye muscles to execute effectively.