The unique practice associated with the Tomato Festival in Spain is the La Tomatina, where participants engage in a massive tomato fight. This festival takes place annually in the town of Buñol and is known for its chaotic, playful nature. Thousands of people gather to throw ripe tomatoes at each other, creating a vibrant and messy atmosphere. The event promotes fun, camaraderie, and a sense of community, turning the town square into a joyous red battlefield.