Boomer

     The Boomer  is an extremely bloated Special Infected.Its mutation has caused it to produce vast quantities of bile which it attempts to vomit on the Survivors temporarily blinding them and summoning a small Horde. Though fragile and slow, the Boomers can be dangerous to a Survivor team whose health or combat abilities are compromised.

the Boomer has short black hair and wears a navy blue shirt and brown pants, both stained with sweat and puke and stretched to breaking point around the Boomer's enormous gut. When idle, the Boomer makes loud burping and gurgling noises which change to loud groans when it sees a Survivor.

If a Boomer encounters a Survivor team at distance and out of range of its projectile vomited bile, it will waddle off into cover and attempt to stalk the team. At closer distances, a Boomer will move into an ambush position (e.g. behind a pillar or vehicle) until the Survivors get within range. However its unrepressed groans and large body make it relatively easy for an experienced team to fix its location and deal to the threat without harm to themselves.

The Boomer has undergone extreme external and internal mutations by some adverse reaction to the Infection. The most notable observation of the Boomer is its extremely bloated belly, most likely caused by its stomach (and possibly most, if not all of its gastrointestinal system) being hijacked by the infection to overproduce bile in massive quantities. The sheer tension on its skin and organs has resulted in a breakdown of the epidermal and dermal layers, causing the skin to become thin and fragile. In some places the skin has even ruptured, exposing some of the bile-filled internal organs. This enormous buildup of internal pressure makes the Boomer quite vulnerable to any outside agitation, as even the slightest gunshot wound or melee shove will result in the Boomer to violently explode, sending blood and bile everywhere - hence its name. Even so, the Boomer can autonomously engage in strenuous self-directed physical activities (e.g. jumping down from a height) without injury.

Other physical mutations observed include massive boil-like growths that appeared upon its skin and face. Whether this is due to overproduction of bile is unknown. Similar to the other Special Infected, it is not distracted by high frequency noises such as pipe bombs or car alarms going off.

The Boomer's bile has a unique chemical binding effect with infected and/or non-infected flesh which produces an extracellular stimulus. This chemical stimulus induces a pheromone-like attraction from nearby common infected which causes them to swarm and attack the bile-saturated source. The exact nature as to why this induces a negative response is unknown but the response is non-discriminatory between infected and non-infected flesh (i.e. using a Boomer bile vial on the Tank triggers the same violent response against the Tank ). It should be noted that typically common infected have been known to exhibit an extremely basic form of logic (hence their ability to recognize non-infected). The bile-flesh response seems to trump this logic, which could mean that the stimulus is extremely intoxicating for the common infected.

