We pulled off a St. Patrick’s Day stunt called the “Rainbow Hi-Jack”—literally projecting a rainbow over a Southern, California restaurant. At the end of this “technological miracle” wasn’t a pot of gold, but something sweeter: the return of the fan-favorite Oreo Cookie Mint Shake.

The cheeky campaign took a playful jab at McDonald’s, claiming a free shake at the end of Jack’s rainbow was far better than a broken ice cream machine at the end of some golden arches.