Zombie, Half-Life Wiki

A Zombie is a common enemy featured in the Half-Life series. It is the result of a Headcrab attaching to the head of a human and taking control over its victim's body, this incapacitates the host, and renders them a "Headcrab Zombie," or a "Necrotic", as they are referred to by the Combine Overwatch. Ordinary Zombies are often referred to as Standard Zombies to distinguish them from the other types of Zombies, such as the Gonome, the Fast Zombie, the Poison Zombie, the Zombine, and the Armored Z

Vortigaunt, Half-Life Wiki

Nihilanth - Combine OverWiki, the original Half-Life wiki and Portal wiki

Zombie, Half-Life Wiki

Zombie Fast, Half-Life 2 Cut Npc's Wiki

Standard Zombie, Half-Life Wiki

Headcrab, Half-Life Wiki

Half-Life - Combine OverWiki, the original Half-Life wiki and Portal wiki

Awakened Zombie (5e Race) - D&D Wiki

Barnacle - Combine OverWiki, the original Half-Life wiki and Portal wiki

Locations of Half-Life - Wikipedia

Half-Life: Alyx Workshop Tools/Level Design/Blind Zombie - Valve Developer Community

Bloody Headcrab, Half-Life Wiki