The ScriptProcessorNode is a part of the Web Audio API, which allows developers to create and manipulate audio in web applications. It enables real-time audio processing by providing a way to write custom audio processing scripts using JavaScript. This node can handle audio data in blocks, making it suitable for tasks like audio effects, synthesis, and analysis. To use a ScriptProcessorNode, developers create an instance and connect it to other audio nodes in the audio graph. It has methods for handling audio input and output, allowing for flexible audio manipulation. However, it is being deprecated in favor of the more efficient AudioWorklet.