Answer: the scapula.
Why ordinary people can't.
Answer: Because ordinary people's bones are not so soft and tough, they can be easily shaped without long-term exercise.
How do you practice?
Answer: Stretch latissimus dorsi and upper limb bones.
What are the benefits?
Answer: It can make bones stronger, less prone to fracture and more flexible. You can do a lot of difficult moves and have an advantage in fighting.