With scientists on the alert for new therapeutics in the face of rising antibiotic resistance, the focus is shifting to specialised viral assassins that can demolish dangerous bacteria.PlyC has been likened to a flying saucer, a doughnut and Pac-Man by scientists from the US and Australian research teams that have spent more than six years trying to take its picture – a crucial step if it is to be enlisted in the hunt for alternatives to antibiotics. Found in a Milwaukee, US, sewer in 1925 where it was feasting on its meal of choice, Streptococcus, PlyC is a protein from a bacteriophage – a type of virus that has evolved over millions of years to kill bacteria, and with great specificity. Bacteriophages, commonly called phages, were discovered in the early 20th century and quickly attracted the interest of doctors as potential therapies. They were used during World War II to treat battlefield infections. But the discovery of penicillin, a drug that tackles more than one type of bacteria, dampened enthusiasm for these highly specialised viruses.