Headcrab

Headcrabs are alien parasites and are the most numerous aliens in both Half-Life and Half-Life 2. There are 3 types of headcrabs: Standard Headcrabs, Fast Headcrabs, and Poison Headcrabs. When they attach to a host, they take control of its nervous system and cause extreme physical changes to its body. Each type of Headcrab produces different variants of Headcrab Zombies.

Types of Headcrabs

Standard Headcrab

Standard Headcrab from Half-Life 2

Fast headcrab

Fast Headcrab. Note the elongated limbs

The Fast Headcrab has longer legs than the normal variety which allows it to move much faster, hence the name. Their greater speed and slightly more damaging attack makes them much more dangerous than Standard Headcrabs, although they are not found in as great of numbers as their cousins. Unlike other headcrabs, it does not have a beak and instead uses talons on the ends of its legs to attach to hosts. These talons also allow it to cling to walls and other surfaces, as seen in Episode One.

Poison Headcrab

Poison Headcrab. Note the prominent fangs near the "front" of the body

The Poison Headcrab (also known as the Black or Venom Headcrab) is the slowest variety of Headcrab but makes up for this with its neurotoxic venom, which is injected via four fangs in its mouth into its host's head. An attack by a Poison Headcrab results in the player's health dropping down to one point. Although they cannot kill the player, Poison Headcrabs are extremely dangerous in the presence of other enemies, and players often target the former before dealing with the other foes.

Trivia

• The Standard Headcrabs are much larger than the ones in Half-Life.
• The Standard Headcrab's entity is npc_headcrab.
• The Fast Headcrab's entity is npc_headcrab_fast.
• The Poison Headcrab's entity is npc_headcrab_poison.