The eruptive burst of laughter—messy, convulsive, and involuntary—appears repeatedly in French poststructuralism as a metaphor for the productive cracking up of subjectivity. This essay posits that the philosophical potential of laughter is taken up in the American context not in critical theory, but in literature. Focusing in particular on the spasmodic howls and jarring barks of laughter that populate Nathanael West’s final novel, The Day of the Locust (1939), I examine laughter not as an emotional response to humor, but as a form of affect capable of convulsing being. To do so reveals the poststructuralist impulses of West’s novel, which explicitly stages the distinction between being and becoming through two different strains of laughter. The first is a self-reflexive laughter, an emotionally legible “ha-ha” that fixes the laughing person as a general type and in so doing camouflages him or her among the crowds of caricatures that inhabit West’s Hollywood. The second is what I term grotesque laughter—an affective overspill that dismantles subjectivity into a series of ontologically unstable performances.