"Pump and dump" is a fraudulent investment scheme where the price of a stock is artificially inflated, or "pumped," through false or misleading statements. This creates a buzz around the stock, attracting unsuspecting investors who believe the price will continue to rise. Once the price has increased significantly, the fraudsters sell their shares at the inflated price, a process known as "dumping." After they sell, the price typically plummets, leaving new investors with losses. This scheme is illegal and can lead to severe penalties for those involved.