the boomer is a special infected which appears to have a bloated belly. the boomer can be identified by its gurgling and burping sounds. it pukes on survivors with a special kind of vomit that attracts common infected to whomever covered in boomer bile. the boomer has 50 hp therefore it is very easy to kill but has some cons. when killed, it explodes which can splash any nearby survivors with boomer bile. the boomer is the only special infected that cannot screech upon spotting a survivor.

how to survive:
-if you hear the boomer and there is no active horde attack, try to kill it as fast as soon as you locate it.
-if the boomer is close to you, shove it back and get a bit of distance between you and the boomer then kill it that way you don't get splashed.
-if a boomer has vomited on you, stay calm as the puke will wear off very quickly. use a melee weapon to kill the zombies that are near you as the puke will impair your vision which could be dangerous if you are in a cramped space with your teammates ahead of you.
-if a boomer has vomited on your teammates, throw a pipe bomb and try to get rid of the special infected swarming affected teammates.
-if a boomer is present but you are fighting off a horde, try to get away from the boomer until you can take care of the boomer(s) present.

the smoker is a special infected with an incredibly long tongue which it uses as a lasso to tangle survivors and drag them to said smoker, if the smoker cannot fully drag a survivor to it instead it will attempt to strangle the survivor where they are. the smoker is taller than normal infected and can be identified by its constant coughing and hacking sounds. it has a massive tumor on the left side of its face and has multiple tongues sticking out of its head and neck. like most other special infected, when it spots a survivor it will make a screeching noise and wait 2-3 seconds before grabbing a survivor. in higher difficulties it will instantly grab a survivor upon spotting them. it has 250 hp but it can be instantly killed by hitting it with a melee weapon.

how to survive:
-if you spot a smoker from far away but far enough where it cant ensnare you, try to shoot it or hide behind an object where it will be forced to come up to you then smack it with a melee weapon.
-if you spot a smoker and it is about to ensnare you, try to get away from it by going behind a corner or other object where it can't grab you then wait for it to come up to you and kill it.
-if a smoker has launched its tongue at you, you can do 2 things:
1: cut the smoker's tongue with a sharp melee weapon. this requires perfect timing and blunt weapon cannot cut its tongue. if you have a chainsaw then just hold down LMB until the tongue gets cut.
2: try to hide behind an object so the tongue misses you. this is possible as the smoker's tongue does not instantly grab you and i've tested this out.
-if a teammate has been grabbed by the smoker's tongue but the smoker cannot be found, shove the survivor, slash the tongue, or shoot the tongue, this will free the teammate that is ensnared in the smoker's tongue, then afterwards you can try to locate the smoker as it takes around 30 seconds for the smoker to regain its tongue.
-if you are grabbed by the smoker's tongue, you have 1-2 seconds before you are constricted. try to use this time to shoot the smoker as much as you can to kill it or at least make it easier for your teammates to kill it. you cannot switch items or swing a melee weapon.
-if there is a smoker present and a horde attack is active, try to get away from the smoker until you can safely kill it with a higher chance of not getting grabbed.

in left 4 dead 1, the smoker does not have a massive tumor and only has 1 tongue.

the hunter is a very agile special infected. it wears a blue hoodie and brown sweatpants. it always had the hood pulled over its face obstructing the sight of its upper face. it can leap far distances and off of walls. it uses its leaping ability to its advantage by leaping and pouncing on survivors. once it pounces on a survivor, it will begin tearing, slashing, and mauling its victim to death. it can be identified by its snarls when it is crawling. it screeches when it spots a survivor that it can pounce on. it is also capable of pouncing on survivors that are incapacitated, it is the only special infected capable of using its attack on a downed survivor. it is the only special infected that is silent while standing up. it runs similar to common infected making it blend in with hordes which can make it almost impossible to avoid. it has 250 hp. it has a defense mechanism where if it cannot pounce on a survivor and it is spot at it will leap back to safety and try to recover its attack. it is the only special infected capable of saving itself therefore, making it one of the most unavoidable and hard special infected.

how to survive:
-if you spot a hunter not close to you and no other targets are active, try to shoot it. remember, it will leap back if it is far from you so be ready to reload many times.
-if a hunter leaps at you, try to dodge to attack by stepping to the side and quickly shove it and kill it as it is able to leap again in a matter of only 1 second, use a melee weapon to quickly kill it, however, the knife takes 2 hits to kill the hunter so i don't recommend using the knife to kill the hunter.
-if a hunter is present and a horde is active, try to dodge its attacks until the horde is cleared or get away from it until it can be safely killed.
-if a hunter pounces on you, there's not much you can do except wait for assistance from your teammates. but if it has not successfully pounced on you, its possible to shove it right before it pounces on you but it requires focus and perfect timing.
-if a hunter has pounced on your teammate(s), shove it or kill it to free said teammate pounced on by the hunter. be careful when you shove it to free a teammate as if it is shoved from a certain angle it will do a roll and quickly attack again, almost so fast that you will be unable to react in time.

in left 4 dead 1, its eyes are barely visible. its eyes seems to be clawed. this may be self-inflicted or a possible cause of the infection. its hood was also less wide and it's sleeves and pant legs are not torn off and it is wearing shoes. his hoodie also does not have a zipper.

the charger is a loud special infected that acts as a zombie battering ram. it has a massive arm with stubby fingers. its other arm has shrunken and decayed to the point that it is flappy and useless to the charger. the charger is half the size of the tank making it easy to identify. it's footsteps are loud when it walks. it wears denim overalls and 1 sneaker on it's right left leg. the other sneaker is missing possibly because his left leg has grown in size to the point the sneaker ripped and fell off of its foot. when it spots a survivor and it is a fair distance away, it will charge at the survivor until it rams into an object or has traveled 80-90 feet. the charger cannot stop or turn during its charge making it possible to dodge its charge. if any survivor is in its way when it charges, it will pick up one of them and send the rest flying through the air. once it stops charging, it will pick up the survivor and smash them into the ground repeatedly until the survivor dies. if there is a ceiling above the charger, then it will throw the survivor into the ceiling as well as slam them into the ground. it has 600 hp making it fairly difficult to kill. it can be killed with 2 hits from a melee weapon but can be killed instantly by hitting it in the head with a melee weapon.

how to survive:
-if you spot a charger and there are no other active targets, try to kill it as quickly as possible as it can knock everybody to their feet which can cause the chapter to restart.
-if you spot a charger and it chargers at you, dont run away from it directly as it is much faster than players at full health when charging, instead, step to the side and wait for it to finish charging then kill it. it takes around 30 seconds to be able to charge again.
-if you are on a ledge and a charger charges at you, get off the ledge and fast as possible, as it can knock you and your teammates of the ledge and kill or incapacitate them, whomever it grabs it can also charge them off the ledge and kill them.
-if you spot a charger and a horde is active, if possible, let the charger charge at you and dodge it if you can, that way you can kill it with the rest of the horde but be careful as its melee attack deals a big amount of damage.
-if a charger grabs one of your teammates, kill it as fast as possible, melee shoves do not affect it as it is too bulky, therefore it is immune to melee shoves in effect and damage.

the jockey is a rather scrawny special infected that lives up to its name. it has a tattered white tank top and blue shorts. it is hunched over which makes it harder to see it it hordes. it can be identified by its constant manic laughter. it leaps onto survivors much like the hunter. when it leaps onto a survivor, it locks onto their head and shoulders and begins clawing at their face and steering them away from the rest of the survivors. during this the jockey will laugh insanely and loudly during the entire time it is riding the survivor. when it incapacitates a survivor it will leap off of the survivor. it takes 30 seconds to regain its riding attack. it has 325 hp making it slightly difficult to kill but can be killed in 1 hit with a melee weapon.

how to survive:
-if you spot a jockey with no other targets, let it leap at you then back up and much as possible and shove the jockey or hit it with a melee weapon. it leaps when it is close enough to a survivor but backing up can easily dodge the attack.
-if you hear a jockey but you cannot spot it, do not go into places that make it hard to dodge its attack, instead if possible wait for it to come out where you can see it then dodge and kill it.
-if you see a jockey and a horde is active, try to get away from it until you can safely dodge it.
-if you are being ridden by the jockey, you have very little control, but with WASD you can try to steer it to your teammates but its unlikely you will 100% succeed.
-if your teammate(s) is being ridden by a jockey, shove or kill it to free said teammate.

the spitter is an ugly looking special infected that spits acidic liquid at survivors which lands in massive puddles. it can be identified by its baby-like squealing. it wears a green crop top and black jeans. upon seeing a survivor she will attempt to get away from survivors that are approaching her then spit at the survivors. after that, she will attempt to run up to survivors and claw them as much as possible until she can spit again. despite being a special infected, she only has 100 hp making her the second easiest special infected to kill. when a spitter dies she leaves a smaller puddle of acid where her body is.

how to survive:
-if you see a spitter with no other targets, wait until she spits then kill her that way she won't attempt to get distance from you.
-if a spitter spits and you are in the range of the spit, get out of the spit because you longer you stand in it the more damage it does to you.
-if a spitter is present and a horde is active, try to avoid her spit and she spits then kill her with the rest of the horde.
-if a teammate is incapacitated in the spitter's acid, revive them as fast as possible otherwise they could die.

the witch is a very VERY dangerous special infected. she wears a tattered brown crop top and she is always crying as if she is scared. she can either be found sitting down or moving around. if she is standing up, she will aimlessly wander around. when a survivor is near her or shining a light at her, she will make growling sounds that will gradually gets louder and louder. as this is happening she will stand up and make herself appear scary. if a survivor continues to be near her or shine a light at her, she will go into attack mode and chase down the survivor who upset her until she attacks them. she is able to incapacitate survivors in one single hit. once she hits a survivor and incapacitates them, she will then begin to frantically slashing and mauling them in a frenzy until they die. after that she will look at the dead survivor in horror and run away from the corpse for a certain amount of time in panic. she has 1000 hp making her very very hard to kill. it is possible to kill the witch with a single shot from a shotgun but i don't recommend trying this unless you're willing to risk it.

how to survive:
-if you spot or hear a witch, try to sneak around her as it's not very wise to try to kill her. do not shoot her as shooting her will make her go into attack mode instantly.
-if you spot a witch and a horde is coming, she is unresponsive to bullets passing her so it is safe to try to kill a horde but keep in mind she gets angry from loud noise and a bullet could accidentally land on her and cause her to go into attack mode if you are using a very inaccurate gun.
-if you wish to kill the witch, the easiest way would be to set her on fire with a molotov and then shoot her down.

the tank is the largest and most dangerous special infected. the tank is loud and destructive and can easily kill survivors. is can also kill other special infected and common infected as well. the thank is massive in size. the tank does not have a shirt, it only has pants and shoes. it is the easiest special infected to identify. it can be identified by it's massive size and it's rageful yelling. it is incredibly strong and can send survivors flying from it's melee attacks. it is capable of ripping chunks of concrete/rock from the ground and hurling it at survivors. it can also hit cars which sens them flying. survivors hit by the cars are instantly incapacitated. it's health varies depending on difficulty:
easy: 3000 hp
normal: 4000 hp
advanced & expert: 8000 hp
versus mode: 6000 hp
it is the hardest special infected to kill and the only special infected that can kill common and other special infected.

how to survive:
-when a tank spawns, focus all of your attention to the tank as it can easily kill your entire team.
-if a tank throws a boulder, wait for it to throw it then dodge the boulder.
-if a tank hits a car, avoid getting hit by the car as it can instantly knock you and your teammates down.