What happens to a stock when a company spins off a large size of its business?

I was watching a video on YouTube (https://www.cnbc.com/video/2024/06/26/how-youtube-beat-netflix-and-disney-in-the-streaming-wars.html) and it got me thinking what would happen stock-wise if Google and YouTube split. One logical thing would be to split GOOG into two tickers each having a value proportional to the value of the company they represent? Any recent precedent? Thanks!