Image: Naughty Dog / PlayStationOfficial screenshot from Naughty Dog / PlayStation.
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.
Throw a Molotov or use the flamethrower first. Burning strips the armor so lighter weapons work, and the shotgun finishes a stunned bloater well. Two shots from a fully upgraded El Diablo or hunting rifle also kill one, and the Power and Armor Piercing rifle upgrades cut the shots needed. A nail bomb on a burning bloater adds a lot of damage. Keep moving: even a burning bloater can grab you.
Each bloater grows three throwable sacs: lower right belly, upper left chest and upper right back. Shooting them off lowers the damage needed to kill it, and removing all three stops its ranged attack completely, leaving it to charge you.
Arrows always break on a bloater. They only hurt it after you crack the plates on its head, so it takes at least four arrow headshots. A machete can hurt one too, but three or four hits up close is risky.
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.
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.
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.
David's Group
David's group are a group of survivors from a town at Silver Lake, Colorado who hunt Joel and Ellie through the winter. You fight them at the University of Eastern Colorado, in Left Behind at the Colorado Mountain Plaza, and around Lakeside Resort.