Being portable, is a vital property of quadcopters. This brings up a new research topic, namely self-arm management. Without self- arm management, the quadcopter needs to be closed manually which is a limitation to functionality and more importantly, autonomy. To best to our knowledge, this paper presents the first self-foldable and self-deployable quadcopter design, named as Folly. This feature makes Folly effortlessly applicable to autonomous systems as it is more compact and transportable. In the design of Folly, we utilized a crank-slider mechanism and spur gears that give Folly the opportunity to automatically fold and deploy its arms in 0.6s. The paper additionally presents real-world experimental results to show the operational efficiency of Folly.