Pra Sang Thong 
Pra Sang Thong is a male character in another famous Thai folk tales.  He was adopted by a female giant named Nang Panturat when he was young not knowing that she was a man-eating giant.  His foster mother disguised herself as a human being when she was with him.  Once in a while, she would go away to find food.  During one of those periods, he surveyed the cave that she forbade him not to enter and found lots of human bones. In this cave, there is also a well in which a human's complexion would change to golden yellow.  He did jump in and so looked as shown in this slide.  Learning about Nang Punturat's true being and afraid that she might eat him one day, Pra Sang later tried to ran away from her.

From Sang Thong by King Rama II