Could you please tell me what is a "grotesque rose" in the chapter Eight of The Great Gatsby?
He must have looked up at an unfamiliar sky through frightening leaves and shivered as he found what a grotesque thing a rose is and how raw the sunlight was upon the scarcely created grass.
In his disillusionment of his dream of attaining his "grail" of Daisy, Gatsby's vision clears in the raw sunlight after his vigil under the gentle light of the moon in his pink suit outside Daisy's window the previous night "watching over nothing." Now, the melancholy Gatsby realizes that in his romantic readiness, he has idealized Daisy's social position, youth, vitality, and wealth--she who possesses an Italian garden redolent of roses, she who uses the word rose insincerely, having called Nick "an absolute rose" after first meeting him, and told Gatsby she would like to put him in "one of those pink clouds." But, her voice is a "deathless song" that promises nothing.
Thus, the grotesqueness of the rose becomes a metaphor for Gatsby's illusive dream of Daisy Buchanan as worthy of his love and devotion. Moreover, the extended metaphor is that of the degradation of the American Dream of wealth and materialism, a romantic dream that ends in corruption and death. It is now
[A] new world, material without being real, where poor ghosts, breathing dream like air, drifted fortuitously about...like that ashen, fantastic figure gliding toward him through the amophous trees.
Indeed, the use of the word grotesque conjures the Gothic world of the preternatural as for Gatsby his world now is because what he has considered "real" has now dissolved like the ephemeral rose.