The Smoker

The Smoker is an Infected with a long, whip-like tongue that can drag Survivors away from their team-mates and use its tongue as an organic noose to strangle Survivors when it is perched above them. Similar to Half-Life's Barnacle, or Resident Evil's Licker. When killed, it leaves a haze of black smoke, distorting the Survivors' vision and disabling character speech. Like most other boss infected, a melee hit from the Smoker does about twice as much damage as the Horde.

Tactics
One of the most deadly if the Survivors are being attacked by the Tank or the Horde. The problem is that the Smoker is generally farther away than a Hunter would be. You'll need assistance from a teammate to un-noose you unless you can quickly shoot it before you lose control. It can sometimes be hard to find the Smoker but the easiest tactic is to shoot it after it has lassoed a teammate because the tongue leads right to it. Your character cannot talk in smoke, only cough, choke, and hack.(You can still type and use voice chat)

On an interesting note, if it is for some reason idle you can hear it hacking and coughing like real life smokers.

Tip: If a fellow survivor is roped and you can't see the smoker to fire at it, punch the survivor, it does no damage to them and they also get released.

Survivors
Tongue Twister Kill a Smoker who has grabbed you with his tongue.

Drag and Drop Rescue a Survivor from a Smoker's tongue before he takes damage.

No Smoking Section Kill 10 Smokers as they are pulling helpless Survivors.

Infected
Chain Smoker Constrict two Survivors on one life as a Smoker.

Specific Tactics