“Aw, you didn't write that!” protested one of the boys. 
“I did,” said Margot. “I did.” 
“William!” said the teacher. 

In this excerpt, one of the children of Venus emerges as antagonist. Though he enters the story as just “one of the boys,” in the teacher’s chastisement of his poor behavior, she calls out William by name. Bradbury’s choice in this moment propels William from the background to the forefront and allows his actions to dominate both Margot and the scene. William’s first act in the story is to challenge Margot’s authenticity. Margot has used her real memories of the sun to originate a short but beautiful ode as tribute. William, who likely cannot remember his first glimpse of the sun, is jealous of both Margot’s memories and her talents. His claim seems to suggest an admiration for her poetic skill and implies that he believes the poem is too exceptional for Margot to have written it. In his outburst, he reveals that he is also impulsive and ill-mannered. The teacher’s quick admonishment suggests that this is not the first instance of William’s inappropriate classroom conduct.

“Well, don't wait around here!” cried the boy savagely. “You won't see nothing!” 
Her lips moved. 
“Nothing!” he cried. “It was all a joke, wasn't it?” He turned to the other children. “Nothing's happening today. Is it?”

Very few details are revealed about William in the story, but this display implies a great deal about his nature. Having lived his whole life on Venus, with no sun and little joy, William has become savage and unfeeling. More concerning, he has become hopeless and nihilistic, and he derives pleasure from sowing cynicism and disillusionment among the other children. In this quote, William attempts to destroy Margot’s hope and infuse the other children with doubt about the appearance of the sun in order to protect himself from disappointment if it doesn’t actually happen. It is also apparent that it is easier for William to believe that they have all been lied to about the sun than it is to acknowledge its possible existence and appearance on this day.