The People who are born on that day have to make a different cermony. The ceremony is special ceremony and hold a wayang sapuh leger ” Shadow Puppet ” peformance.
Acording to Lontar Sapuh Leger and Dewa Kala ( a small vertical book in which the ancient Hindu teaching are written, whitch is made of dried, pressed, and blessed palm leaves ), Wuku Wayang is a sacred period when a Dewa Kala ( Evil in Balinese mythology ) was born.
Balinese people belive that the children who was born in Wuku Wayang is a part of Dewa Kala,

so the children must purified by the Sapu Leger ceremony and hold te wayang kuli ( Shadow Puppet ) performance.

Tumpek Wayang is a special day for shadow puppet arts. its occurs every 210 days in Balinese Calendar System. Shadow puppet have another name whitch is Sanghyang Ringgit, whitch mean thats the art is grifted by the power og Shangyang Widi (GOD ).
Its an integral part of Balinese life. Its performed when people have ceremonies such as purification for children born on Wuku Wayang. So the Shadow Puppet performance in Bali is not only to entertain but also represent a kind of sacred art form.