THE LAST OF US - The Clickers Attack Joel Tess and Ellie in The Museum Scene

Clickers are the third stage of the infected in The Last of Us, The Last of Us Part II, and Left Behind. They take roughly a year to reach this stage of infection after exposure to the Cordyceps brain infection. They have had prolonged exposure to the fungus, and now possess strength that significantly surpasses the average human.

Clickers appear less human than runners and stalkers, with faces that are completely skewed and scarred by fungus developed from their infected brains, often only leaving behind a maw of jagged teeth. By this point, whatever clothes the host may have been wearing are mostly tattered and destroyed. Clickers claw and scratch the fungal growth on their eyes as if trying to get rid of their blindness, especially when immobile. The growth forms large patches of scale-like tissue that glow in the dark. The patches are seemingly an earlier stage of the fungal infection growing out of their hosts' bodies. These fungal plates have adapted to keep the host alive and able to spread. In fact, a direct shot to the face with a powerful weapon such as a revolver will only break off a chunk of the mold, leaving the clicker's brain unharmed. This makes them deadlier, but at the price of being completely blind due to fungal infection taking over their face.[5]

However, clickers are able to maneuver through areas by utilizing echolocation, which produces noticeable clicking and screeching noises to locate sources of sound, hence their name. Like runners, clickers can sometimes be found in a passive state.

Clickers are dangerous and much more aggressive than runners and stalkers, with the human host no longer conscious enough to resist the infection to the extent as the latter two.

Clickers also possess high intelligence, never leaving an area when they have heard prey run by them, and will constantly check every available nook and cranny to locate the source of the sound with little regard to giving up on the task at hand. However, their echolocation is crude compared to creatures like bats, as they will not notice that something is alive or moving unless it is directly in front of them. This supports the assumption of the front being where the clicks are sounded, as their face plates are shaped like a megaphone, directing it straight ahead of them, but not all around.

When provoked, a clicker will immediately enter into a "berserk mode," aggressively flailing its arms and 'roaring'. At this point, if a survivor has been "spotted" by a clicker, the clicker will attack head-on and will not flinch when shot, unless the player is using high-powered rounds.