In the audio titled "075770_56. Fast Flutter2.wav", you will experience a rapid succession of light, flapping sounds. It's reminiscent of a small bird or an insect rapidly fluttering its wings. This is a sound effects audio, typically used in foley work to create a more immersive environment in media productions. The flutter is fast-paced, creating a sense of urgency or excitement. Despite the speed, there's a certain lightweight and delicate feel to the sound, much like a butterfly hastily flapping its wings.