No, it's not a joke. But the chances are slim. They are not zero, in any case. Are you sure you want to take the risk of being hit by a ten-story, twenty-three-ton rocket hurtling towards Earth at thousands of km/hour? We are pretty sure you wouldn't. But you can still stargaze; maybe the rocket debris will fall near you? It would be cool to upload on YouTube, make millions in days!
China's largest rocket, called Long March 5B, has lost control and is now tumbling towards Earth at a very high speed. The missile is expected to hit Earth on the weekend, and the phenomenon is called "uncontrolled re-entry." The scary thing is, nobody can predict at the moment where it will fall. It could fall in the seas or oceans or might even fall on land and populated areas. Probabilistically speaking, more of Earth's surface is covered with oceans, so chances that it'll fall in an ocean are high.
Since nobody can control what has already happened, the next big question to arise is why China has allowed this to happen in the first place. It has happened once before too. China has been launching rockets at a fast pace, and given its track record, the same can happen in subsequent years. China has undoubtedly been edging closer to the USA's space supremacy, e.g., the former country took rocks from the moon and returned them to Earth and even put a spacecraft in Mars orbit. But due to unknown reasons, it has not been able to control the trajectory of rockets launched by it.
The pieces that will fall on Earth uncontrolled are the upper stage rocket parts that usually make a controlled entry after releasing their payloads (i.e., the space stations or their parts). The discovery was made by Aerospace Corporation, a non-profit organization and which also predicted that the rocket would fall on Saturday at 11:43 pm. With China, a pattern of irresponsibility is emerging. For example last year in May, a Chinese rocket fell off into the Atlantic very close to West Africa. This was a very heavy load, the equal of which is not found in the 21st century. Similarly, the Chinese first space station called Tiangong-1 crashed into the Pacific in 2016. Though annually around 150 tonnes of space wreckage falls to Earth and there have never been any casualties yet but if the Chinese wild behavior continues, people may lose lives one day.