A rapid mixer cocktail shaker, also known as "The Rapid," is a vintage mechanical cocktail shaker designed to efficiently mix and chill drinks using a plunger-style mechanism. Unlike standard hand-shaken cocktails, "The Rapid" utilizes a built-in paddle or spoon within a glass jug to quickly agitate the ingredients and ice. This design was intended to provide a more rapid and effective chilling and mixing process compared to traditional hand shaking.