Clickers are blind stage three infected that find you by the clicking sound they make. Their grab kills instantly unless you carry a shiv and have the Shiv Master upgrade, so most players deal with them quietly or with fire.
Stay low and slow. A shiv kills a passive clicker even from the front, and an active one from behind. The bow needs a headshot or two body shots and the arrow usually breaks on the fungal armor. Bricks and bottles pull them away from your route.
The shotgun, El Diablo and the flamethrower are the surest kills. A Molotov thrown into the middle of a group works well: they rush toward the sound of breaking glass and walk into the fire. A stunned clicker can also be finished with a sprinting melee strike after a brick hit.
With a shiv and at least the first level of Shiv Master, Joel can stab a clicker that grabs him from the front. On Easy you get this for free. In Left Behind, Ellie's switchblade kills an unaware clicker from the front if you wait still for it to walk up to you.
FEDRA
FEDRA, the Federal Disaster Response Agency, is the military government that runs the Boston quarantine zone. Its soldiers are the best-equipped enemies in the first chapters, and you fight them while smuggling Ellie out of Boston.
Infected
The Infected are people taken over by a mutant Cordyceps fungus, and they are the main threat between every human fight in The Last of Us Part I. In Part I and Left Behind you meet four stages: runners, stalkers, clickers and bloaters, each harder to kill than the last.
Runner
Runners are stage one infected, people turned within the last couple of days. They still see, move fast and swarm in packs, so the danger is numbers rather than any single runner.
Image: Naughty Dog / PlayStationBloater
Bloaters are stage four infected covered in armor-like fungus. They are slow and blind but kill you instantly if they grab you, and they throw bursting sacks of mycotoxin from range. Fire is the way to beat them.