Bloaters are the fourth, rarest, and most dangerous stage of the infected in The Last of Us and The Last of Us Part II. They take years to develop and reach this stage after years of exposure to the Cordyceps brain infection.
Bloaters are incredibly strong infected that are covered in thick fungus that effectively acts as armor. As such, their skin forms large patches of scale-like tissue that glow in the dark, which form their mykotoxin pouches and engulfs their entire body. Because of this protective covering, they can withstand multiple hits from weapons such as the Shotgun and Hunting rifle, and even hatchets and machetes, making them extremely tough to eliminate. Some bloaters are also impossible to kill outside of cutscenes, like the one Joel and Ellie face in the Wyoming hotel.
Bloaters are extremely aggressive, but are rather slow-moving, making them more predictable than other infected. Like clickers, bloaters 'see' using echolocation to locate and trap a survivor. Because the fungus has completely deformed their face and blinded them, their echolocation is much less refined than the clickers.
If a bloater grabs a survivor, it will violently rip their jaw apart through brute strength, grab the player's head and smash it, pin them to the ground and pummel their body mercilessly, or grab the survivor's neck and bend it to break the spine, killing them instantly. There is no way for the player to defend themselves if grabbed - the result is an instant kill. Bloaters throw sacks of mycotoxin, which explode on impact, spraying the target with the toxin. The mycotoxin will hurt the player over time, so it is recommended to avoid these deadly clouds.
Bloaters, like all infected, are vulnerable to fire, making fire weapons ideal for when several bloaters are present. When set ablaze, a bloater will wildly thrash around, trying to put out the flames. After being immolated, they will be charred, black, and smoking. Their armor will also be charred and brittle, making them vulnerable to low-powered weapons. Despite this weakness, fire-based weapons such as flamethrowers or Molotov cocktails still require multiple uses before killing a bloater. Their other, less effective, weakness is armor-piercing rounds from an upgraded weapon, like the hunting rifle. It will take fewer shots to kill if the weapon has the Power and Armor-Piercing upgrades.
Furthermore, despite their tough fungal armor, they are not immune to melee weapons as long as enough force is exerted on them. Joel was one of the few people to demonstrate this, as he was able to hack a bloater to death while also amputating its arm with two hits from a machete.
The most efficient way to kill bloaters is to throw a Molotov cocktail or use the flamethrower on them, due to their vulnerability to fire. When they are stunned, the shotgun is the next most effective weapon to kill the bloater with. However, a burning and thrashing bloater can still grab the player and kill them, so under no circumstances should one ever let a bloater get within melee range. To counter this, two shots from a fully upgraded El Diablo, hunting pistol or Hunting Rifle, are also enough to kill a bloater.
Another efficient way to damage bloaters is to throw a Molotov Cocktail, then use a nail bomb while they are on fire. Do not get too close, however, as it will always charge at the player.
The bloater actually draws its mycotoxin bombs from bright, deformed patches growing on its body. Each bloater has three: one on its lower right abdomen, one on its upper left chest, and one on its upper right back. Shooting any of these growths destroys them and reduces the damage required to kill the bloater. Destroying all three will completely disable the bloater's ranged attack, limiting it to charging at the player. This significantly increases the player's options for dealing with the bloater, as it can no longer harm the player from a distance and is easily lured into traps. If unable to destroy them, the bloater will take a short amount of time to throw the sack of fungus; when they then raise their arms, run away from the direction the bloater is throwing the sac.
When dealing with a runner, stalker or clicker, if the player has access to a brick or empty bottle, as well as a blunt weapon, the player can stun the infected by throwing the object at it, and then continue by running towards the infected while swinging a melee weapon. This will result in an instant kill. However this is ineffective against a bloater, as its hardened face is impervious to thrown bricks and bottles and standing still may invite it to lob a fungus bomb at the player or close in for the kill.
In The Last of Us, running in different directions, stopping and then firing one shot is time consuming, but it will work after many shots. If they run out of ammo for the shotgun, they can quickly switch to the hunting rifle. This is also viable on the higher difficulties, as one is better off avoiding enemies altogether to conserve ammunition or when they have run out of Molotov cocktails and nail bombs. In Part II, the player can make use of the dodge mechanic to avoid the bloater's charge attacks and lure them into ramming into solid walls, which will stun the bloater. Dodging does require skillful timing to pull off though. Even though bloaters move slowly, their charging can catch players off guard, so it is advised to avoid becoming cornered when avoiding a bloater's grapple; spatial awareness is key to avoid being trapped.
While bloaters are a frequent encounter in both games, they are not a mandatory enemy to fight. For instance, in Pittsburgh, the University, the Salt Lake City sewers and the Seattle Hotel, the player can avoid fighting these enemies if they wish. However, the bloaters encountered in Wyoming, Lincoln, the Seattle Arcade and at the Lakeside Resort must be fought and successfully defeated.
- In The Last of Us, if the bloaters in the Pittsburgh hotel basement and UEC dormitory kill Joel, they will actually knock the mask off of his face in a special death animation.
- When controlling Ellie, the bloater death scene changes; the bloater simply punches Ellie, killing her with its sheer strength.
- Bloaters are the only stage of infected from The Last of Us that do not appear in the Left Behind DLC.