Shaker scoop

A shaker scoop (sometimes called a shaker hood scoop or a shaker hood) is an automobile term for an air intake for combustion air that is mounted directly on top of the engine's air cleaner and protrudes through a hole in the hood. Since it is fastened directly to the engine, it moves with the engine's movement and vibration on its mountings, thus the 'shaker' name.
Some official Chrysler literature referred to this popular hood style as the "Incredible Quivering Exposed Cold Air Grabber". This lengthy title has since been shortened by enthusiasts and collectors to the less tongue-twisting "shaker hood". 
Like all such scoops, its purpose is to increase performance at high speed by a 'ram air' effect, delivering high pressure air to the engine. However, engines draw air in hundreds of cubic feet per minute so scoops are not practical to raise intake pressures significantly. Other benefits of a shaker hood include elevation to prevent water from being drawn on flooded terrain, a cooler source of air, and a more direct path to the engine's throttle plate.
Such scoops were fitted to a variety of cars, including: