The Last Of Us Season 2 Just Secretly Retconned An Old Infected Stage
This isn’t even their final form.

The Last of Us is a show about zombies, but don’t call them zombies — they’re “Infected” and only “Infected.” But even within that group, there are different terms for different stages of the cordyceps infection, from the manic “Runners” to the massive “Bloaters” that serve as minibosses in the game and major obstacles in the series.
However, one of the major stages of Infected wasn’t seen in Season 1. Now, in Season 2, they’re being treated as something completely new, even though they were relatively common in the game — completely changing what we know about the infection as a whole.
The ultra-smart “Stalker” from The Last of Us Season 2.
In The Last of Us Season 2 Episode 1, Dina and Ellie explore an old supermarket and Ellie faces a new kind of Infected she’s never seen before. Instead of running frantically at her like a Runner or using echolocation to detect her like a Clicker, this Infected waits patiently to sneak up on Ellie, something she’s completely unprepared for.
After the encounter, Dina and Ellie speak to the Jackson council about this new discovery. “I'm not saying it could do math or anything, but it didn't run at me,” Ellie says. “It did what we do... took cover, planned, waited, lured me in. Stalking.”
For fans of the original game, this behavior is nothing new. Stalkers play a more prominent role in The Last of Us Part II, but they’ve been around since the first game. In fact, players can find a handout among Joel’s belongings in the second chapter of The Last of Us, explaining each stage of infection.
A military pamphlet from The Last of Us game shows the stages of infection, including stalkers.
First are the runners, with the description “Cordyceps has taken over the victim's motor functions. Fast and agile. Stage 1 infected usually travel in packs. Do not let them swarm you.” Then are the stalkers: “Uses environment to ambush victims, will frequently flank and attack from behind. Approach with caution and check your surroundings.” The third stage, the clickers, are described as “Completely blind, acute hearing, uses echolocation to seek out prey. Keep your distance! Stage 3 infected are known for their ferocious attacks and are extremely lethal.” The information on the fourth stage, the bloaters, is ripped from the page, so the appearance of one later in the game is a surprise.
So while stalkers in the game are old enough to appear in initial FEDRA pamphlets, in the series, they are a completely new evolution of Infected never before encountered. They’re clearly more ferocious than even Clickers — the one Ellie confronted managed to get a nasty bite out of her. It’s likely they’ll become a major enemy in Season 2. However, there are still many other evolutions of Infected we haven’t seen, like Shamblers and Rat Kings, so this may just be the start of cordyceps discoveries.