In The Picture of Dorian Gray, what peculiar phenomenon happens to Dorian Gray's portrait?

In "The Picture of Dorian Gray" by Oscar Wilde, the phenomenon that occurs with Dorian Gray's portrait is that it decays while he remains youthful. This mirrors the central theme of the novella, which explores the relationship between beauty, morality, and the consequences of a hedonistic lifestyle. As Dorian indulges in a life of excess and vice, the portrait becomes increasingly grotesque, reflecting the moral degradation of his soul, while he maintains his outward appearance of youth and beauty. This stark contrast between Dorian's physical form and the deteriorating portrait serves as a powerful commentary on the superficiality of appearance versus the reality of one's character and actions. The haunting effect of the portrait ultimately leads to Dorian's tragic realization about the true cost of his choices.