Dzus (pronounced "zoose") fasteners are a cleverly-designed type of fastener invented in the 1930s by engineer William Dzus.
They're designed to engage or disengage with just a quarter turn, making them ideal for affixing panels that frequently need to be removed, like an inspection panel on a machine or vehicle. Chances are you've driven a car that has a plastic panel or two in the trunk, held on by Dzus fasteners. You also may have seen them used on exterior panels at custom car shows.
A spiral cut into the tip of the shaft engages with a wire spring, locking into place.
They come in a wide range of variants. Some require a driver to turn them, others have a butterfly grip or pivoting loop for tool-free operation. Some have a spring assembly that allows them to self-eject, in a captive position, when released.
If you're interested in learning more about Dzus fasteners, I can recommend this video from Car Builder Solutions, which runs down different methods of measuring and fitting them. If you want to skip to a particular part in the vid, I'll include some jump links below the vid.