The video is on the long side, but it explains what short sellers do, how they make money, and what companies do to fight short sellers.
This part spells outs the main motivating story in my paper with Melissa Prado and Jason Sturgess:
"Coincidentally, large investors in the company chose to withdraw some stock from the pool available to borrow, leaving short sellers wary they would be forced to close positions and brokers working to find stock to lend. The share price swiftly rebounded."
