A prophage is a form of a virus, specifically a bacteriophage, that has integrated its genetic material into the DNA of a host bacterium. In this state, the viral DNA is called a prophage and can remain dormant within the bacterial genome. This allows the virus to replicate along with the bacterium during cell division without causing immediate harm. When conditions are favorable, the prophage can become active, leading to the production of new virus particles. This process can result in the lysis, or destruction, of the host bacterium, releasing the new viruses to infect other cells. Prophages play a significant role in the life cycle of bacteriophages and can influence bacterial evolution.