In laboratories where the boundary between biology and computation has grown thin, scientists have done something quietly extraordinary: they asked an artificial intelligence to imagine viruses that nature never made, and the viruses worked. Published in Science, the research describes how AI-designed bacteriophages — living medicines conjured from learned patterns in DNA — defeated antibiotic-resistant bacteria that natural viruses could not overcome. It is an early signal that medicine may soon be able to design its own evolutionary answers to one of its oldest and most dangerous adversaries