"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 can involve promoting the stock on social media or through other channels to create hype and attract unsuspecting investors. Once the price has risen significantly, the fraudsters sell their shares at the inflated price, which is the "dump." After they sell, the price typically plummets, leaving other investors with losses. This practice is illegal and can lead to severe penalties for those involved.