Runners: The first and weakest stage of infected, they are defined by their speed, clumsy attacks and their tendency to swarm their targets. Clickers: The second stage of infected, clickers are more fungus than human—with the exception of their mouth and teeth, which remain intact to snap at victims. Bloaters: The last and strongest stage of infected, like Clickers, Bloaters are blind and rely on echolocation to locate their prey. Tartaglia: Strong, loner, well prepared.