The Special Infected
In Left 4 Dead 1 & 2, there are more Zombies but they have special Abilities. They are:Boomer
Boomers are fat, nasty zombies that can puke on you that attracts the Horde. If you kill them, they explode and they can explode on you and it will attract the Horde.
Boomettes are just girl boomers.
The Hunter is a medium size, boy Zombie that has the ability to pounce from a long distance. When on a survivor, it will bite and claw you .
The Smoker is a unique Infected. It has multiple tongues that strangle you and pulls you towards the Smoker. They can be found in high altitude areas. Also, when you kill them, they emit a green smoke.
The Tank is a muscular zombie who can pick up chunks of rocks or cars to throw at the survivors, or punch them away with its immense strength. A single tank usually requires all four survivors to kill or else it will devestate them.
The Witch is a female zombie who cries in a corner on L4D or walks around crying in L4D2. Though she seems harmless, she is actually more dangerous than the tank, able to incapacitate a survivor no matter their health. Most players attempt to sneak past a witch, for this reason. Thankfully, if she kills the survivor who upset her, she runs away.
The Spitter is a female zombie who spits acid at the survivors. Like the boomer, who explodes in the bile they use on survivors, she will explode on death, leaving behind a pool of acid.
The Jockey likes to jump on survivors and drag them to dangerous location, such as hordes, witches and spitter acid. Thankfully, they are very fragile, so killing them once you see them isn't a problem, unless they get you.
The Charger is basically a half-tank. The right half of a charger is deformed to be like a tank, while the left half has a comical shrivelled-up arm. A charger will shoulder-barge anyone in its way, picking up the survivors and smashing them into the ground if they get caught by it.