Half Life 2 Fast, Poison, Regular Zombie sounds

When a standard headcrab successfully attaches to a host, the host becomes a standard headcrab zombie. The torso of the host is open and the organs can be seen. In Half-Life 1 the player can see the texture of the host's skull on the headcrab. However, this is removed in other installments. They are slow-moving but powerful, using their claws to beat their victims to death. They moan almost constantly, and growl when they detect prey. Because headcrab zombies are slow, they are often found in confined spaces and/or in large numbers to compensate. In addition, standard headcrab zombies will often feign death until the player approaches, catching them off-guard. In Half-Life 2, they can swat loose objects on the ground when they run into them, creating potentially lethal projectiles. Half-Life 2 also introduced still-moving zombies which are severed at the waist; these half-zombies crawl toward the player using their arms. When a fast headcrab attaches to a host, it produces a fast headcrab zombie. These zombies are stripped of their outer skin, some body tissue, and most or all organs, leaving large parts of the victim's skeleton exposed. Fast headcrab zombies can run at great speeds and have the unique ability to jump and rapidly climb rain gutters. They also move on all four limbs, but stand on two legs when attacking a victim. Fast zombies betray their presence with several vocalizations. While running along the rooftops they emit an echoing wail; while running they give a frenzied growling; as they jump into attack an enemy they release ear-piercing scream; and when injured they freeze and groan loudly. A fast headcrab zombie's usual method of attacking, when given a clear distance to its prey, is to leap forward several yards to tackle and claw it into the ground. In Half-Life 2: Episode Two, the fast zombie can be seen jumping on the front of the players vehicle, and melee attacking until Alyx Vance kicks it off. Despite their speed and physique, fast zombies are much weaker than ordinary zombies in terms of damage they inflict, though they have the same health as standard zombies. Though they are not as common as standard zombies, they often attack in groups of two to three and can be difficult to hit due to their speed. In Episode Two, fast zombies also come in a torso-only variant, and are still much faster than other zombies. Poison headcrabs produce the poison headcrab zombie, a bloated, reddish/purplish, slow-moving and hunched-over "carrier" for several poison headcrabs. A fully-loaded zombie carries four headcrabs including the host's controller. It is the strongest and most resilient form of headcrab zombie in terms of damage capability and overall health, but also the slowest. A poison zombie reveals its presence with its distinctive, strangled, heavy breathing and muffled moans. Like other zombies, it tries to beat its prey to death, but its most dangerous weapon is the extra poison headcrabs it carries, which it can throw at the player with an elephant-like bellow.