Zombie

"Ugh... that smell can only mean zombies."

- Alyx Vance

The Zombie is a common enemy featured in the Half-Life series. It is created when a Headcrab attaches to the head of a suitable host and takes control over its victim's body, rendering the host a "Headcrab zombie," or "necrotic", as they are referred to by the Combine Overwatch.

Overview
Ordinary Zombies are referred to as Standard Zombie to distinguish them from the other types of Zombies, such as the Gonome, the Fast Zombie, the Poison Zombie and the Zombine.

As their name suggests, zombies do not appear to retain much of their former intelligence and, like Headcrabs, will blindly pursue their prey, oblivious to danger (such as the propeller traps seen in Ravenholm or the weapons used by their prey). Zombies do not respond to fire, and will walk blindly into it, though they feel it on them and notice they are burning once they are on fire, and feel the pain of burning from it. Zombies mainly attack with swipes from their claws, but in Half-Life 2, they gain the ability to forcefully punt objects towards the player. Also in Half-Life 2, certain Zombies can be found "sleeping" and stand up to attack the player if they get too close or are attacked, as if they were playing dead.

As Headcrabs do not attach themselves to native Xen creatures, Zombies are only found on Earth, usually in remote or deserted areas.

Zombification is also one of the ways used by the Combine to subject and intimidate the human race. Headcrab Shells will often be sent to Resistance camps to dismantle them, turning the Rebels stationed there into Zombies with the use of Headcrabs. This is notable for the Rebel outposts along the City 17 Canals (in and beyond the Underground Railroad) or in cases like Ravenholm.

It is not currently known if a person is technically alive after turning into a zombie. However, the groaning that standard zombies constantly make in Half-Life 2 are heard as a victims' muffled attempts to yell for help. This seems to indicate that a victim is likely alive and at least somewhat aware of their situation. And, indeed, ripping a headcrab off of a victim shows that a victim's head is bent upwards at an irregular angle, with a terrified look and a violent scream to match frozen onto their face. However, the person is likely dead due to their torso having been ripped open. The groan can easily be explained as simply being a sound the Headcrab influences the body too make.

A Headcrab's attack does little damage (with the exception of Poison Headcrabs), and it also takes some time for Headcrabs to take over their hosts, who are initially still in control; however, Headcrabs both attack very swiftly and (should they succeed) latch onto the head very firmly, so that any attempt by a struggling victim to remove the parasite with their hands is largely futile. Coupled with disorientation and the imminent loss of consciousness from suffocation, this ensures that most victims nonetheless succumb very quickly, explaining the exceptional effectiveness of the Headcrabs' use by the Combine.

It is not known for sure if a victim of a Headcrab attack can still be rescued once a Headcrab has attached itself onto their head. Gordon Freeman's sole attempt to do this at the infested Station 6 apparently failed, killing both the Headcrab and its victim, which suggests it is not possible.

Trivia

 * An unusual characteristic of the Poison and Fast Zombie variants is that only three middle fingers of the five on each zombie's hands develop into claws, compared to all the fingers on a Standard Zombie.
 * An often-overlooked effect that signals a Zombie's presence is the buzz of flies due to the rotting flesh and bodies that can often be found around them.
 * On Station 6, a Standard Headcrab can be seen latching onto a rebel's head, turning him into a Zombie.
 * If spawned in Portal, a Zombie will disintegrate when it stumbles into an Aperture Science Material Emancipation Grill, as will a Headcrab.

List of appearances

 * Half-Life: Day One
 * Half-Life
 * Half-Life: Uplink
 * Half-Life: Opposing Force
 * Half-Life: Blue Shift
 * Half-Life: Decay
 * Half-Life 2
 * Half-Life 2: Raising the Bar
 * Half-Life 2: Episode One
 * Half-Life 2: Episode Two