Cauliflowers can grow so fast that you can actually hear them growing. The “cauliflower creak” is a distinctive squeaking noise caused by the vegetable growing at a sudden rate, forcing its florets to push against one another. – WTF Fun Facts
Source: https://www.vice.com/en_us/article/53j4p8/listen-out-for-squeaking-cauliflower-this-weekend