The first infected stage. An infected human will enter this stage within two days. Their significant characteristic is their incredible speed. Runners still have their eyesight unlike clickers. Since their anatomy is still similar to the non-infected human their vocals have not had a significant change. Some players argue you can hear faint cries and moans coming from an idle runner. Like I have mentioned, runners are known for their insane speed – hence the name.

The second infected stage. An infected human will typically reach this stage between two weeks to a year. Similar to runners they have received their name due to an outstanding characteristic. Stalkers stalk. Some stalkers will mimic a dead host by latching onto a wall and allowing the cordyceps to fester whilst it patiently waits for its next victim to walk past. Stalkers tend to hide during combat and attack once it has the opportunity. You can often catch them running from corner to corner or attacking you from behind.

The third infected stage. Humans that reach this stage have been infected for at least a year. By this time cordyceps have blocked the host’s eyesight, so the clickers use echolocation to locate its prey. You should avoid any combat and stay quiet near a Clicker. Stealth will be your best mate with these infected. Again, their name is based on a characteristic. Clickers tend to make a clicking sound. By using their vocality they will identify their prey’s status – whether it is alive or dead, since the clicker’s echolocation cannot identify whether its prey is alive unless it is standing right in front of it. Their screeches will signalize if anything that is alive is positioned in front of them.

The fourth and most dangerous infected stage. The unfortunate hosts that are stuck roaming the world in this stage have been infected for well over a decade. Because they are so rare, bloaters do not appear often in game. Bloaters will throw acidic spores at their prey from a distance. They are the only infected that can attack its victim from a distance. Bloaters are covered in cordyceps. Their thick fungi shell makes them difficult to kill them. The best way to kill off a bloater is by using fire. As Joel and Abby, you are given a flamethrower. I guarantee you, it will come in handy.

Shamblers are the mutation that was introduced in The Last Of Us Part Two. It is believed that because of the humid environment in Seattle – clickers mutated between stages three and four to better endure the humid air. Cordyceps in our universe are very fond of humidity and spread faster in humid areas. Shamblers are not as physically benefitted as clickers and bloaters, but expel large acidic spore clouds – wounding their prey at a larger radius. When a shambler dies, they release one final blow with acidic cordyceps spores into the air.

The Rat King consists of multiple infected that combined into one at the hospital in Seattle. We meet The Rat King when playing as Abby, but you can also hear it screech when playing as Ellie. The Rat King had evolved for over twenty years, because on outbreak day workers at the hospital locked up thousands of infected in the hospital basement. The Rat King primarily consists of bloaters, stalkers and clickers. The Rat King is the strongest case of infected but does not count as an official stage or mutation since it is mainly a combination of various infected stages.