A Spicy Prank Becomes a Fire and Ice Cream Collaboration by Two San Francisco Brands

April Fool's Day has notoriously spawned unusual, unpalatable--and mercifully nonexistent--flavor mashups for the sake of a good laugh in brands' quest to connect with customers. But in the case of two San Francisco-based brands, what began as a prank unexpectedly morphed into a quirky collaboration of fire and ice cream to the delight of their...