Dollar flu The Division
With an innocuous start that’s very much like the common cold, the dollar flu is terrifying because of how plausible it seems. While it starts out like the beginning of flu, with fevers and aches etc, it’s actually a strain of smallpox that’s particularly dangerous because it’s infectious even when you’re not showing symptoms for it. Yet it has no cure, resulting in a population-unbalancing mortality rate. The death rate is so bad it leads to an apocalypselike scenario and complete collapse of society. Those who survive are left to fight over the scraps of food and water that remain, leading to violence. Even if you’re lucky enough to be immune there’s still a high risk of dying at someone else’s hands as you fight over the last bag of rice on a supermarket shelf.