In the long human struggle against cancer, the body's own immune defenses have often thwarted the very therapies designed to heal it. A team of researchers has now turned this paradox inward, engineering tiny vesicles harvested from dying immune cells to carry oncolytic viruses past the body's sentinels and directly to tumor tissue. The approach — a kind of biological disguise drawn from the machinery of natural cell death — achieved striking efficiency in laboratory conditions, raising cautious hope that the delivery problem haunting viral cancer therapies may one day yield to biomimicry.