Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. It was the vocal fry heard and mocked ’round the internet: “Genes are passed down from parents to offspring, often determining traits like hair color, personality, and even eye color.” A pause, as a lounging Sydney Sweeney zips up her jeans, then looks up with her big blue eyes: “My jeans are blue.” Genes, jeans—it’s a pun, get it? That wordplay is the foundation of Sweeney’s new ad campaign, filmed for the clothing retailer American Eagle to promote new...