Youths' affinity for snack foods is well-documented; in various contexts, they sell chips, candy, and other goods. Adults may frame such sales as either entrepreneurial or deviant, which can contribute to positive youth development (on one hand) or cycles of disengagement and criminalization (on the other). Drawing on ethnographic and interview data from Hamilton High School, I show how adults' criminalization of snack sales led the activity to more closely resemble that which they feared: drug sales. Snack sales constitute one way in which youth exercise agency in the face of broad institutional control, leading some to challenge the legitimacy of the school overall. These findings represent a case of how youth experience "criminalized childhoods" in a school context.