As everyone has probably heard, antibiotics are less and less effective and there are fewer and fewer replacements for failing drugs in the pipeline. So what would happen if you got an infection that was resistant to all the known antibiotics? Would you die, or is there something else doctors could try as a last resort? One surprising answer is that they might treat you with viruses from pond sludge. As postdoctoral research biologist R. Fredrik Inglis explains, this is an old remedy that is now getting a new look.