"—Red hair and more children than they can afford." Malfoy turns and glances at Mayumi, "And I'll bet you're another one of those Weasley spawn."
Mayumi stared at him for a few long seconds, before she glanced at the empty milk carton in her hand, and shrugged before throwing it up and down several times.
"This bitch empty," she catches the milk carton, "YEET!"
The paper box nails the centre of Malfoy's forehead beautifully, and the compartment defends into chaos.