Designer phages might be a promising and innovative technology in the future. Imagine creating and using viruses that infect and kill bacteria, using genetic engineering and synthetic biology to modify and customize them. Imagine using designer phages for different purposes and applications, such as medicine, agriculture, biotechnology or biowarfare. Imagine the benefits and risks of designer phages, such as fighting antibiotic-resistant infections, enhancing crop yields, creating new products or weapons, or causing unintended consequences. Designer phages might be a powerful and versatile technology for the future biologists.