This article is about the enemy. For the weapon, see Barnacle Grapple.
Barnacles are alien creatures featured in the Half-Life series.
Barnacles are stationary carnivorous alien creatures with limited intelligence. They typically hang in clusters and use dark places to surprise their prey, usually around a blind corner. Physically, they resemble a large mouth full of sharp teeth with a giant elongated tongue. When killed, they drop an array of partially digested body parts. They occasionally regurgitate pieces of recently consumed prey while idle.
They attach themselves to the ceilings and wait. When a victim passes beneath a Barnacle, it snatch its prey with its tongue, pulls it up, and clamps it in its mouth for few seconds before completely devouring them. If the player gets caught, he must immediately kill the creature before getting dragged up too high or risk suffering damage from the fall.
In Half-Life, Barnacles only attack humans. Characters appear to ignore the presence of Barnacles in any condition. When a victim is attacked by a Barnacle, they become immobilized and struggle during this sequence. The player is able to save the victim by killing the creature, allowing the victim to simply drop unharmed.
 Opposing Force
In Opposing Force, the player comes across a Barnacle that was detached by the science team. This Barnacle can be used as a weapon to pull and eat small creatures, or as a grappling hook to latch on organic surfaces to reach some areas.
 Half-Life 2
In Half-Life 2, Barnacles now instantly kill their victims when they latch onto them with their tongues. They attack everyone, including alien creatures. They're able to grab objects scattered around the levels and attempt to ingest them. This technique can be used to distract the creature and bypass it. If the object is not edible, they will remember and ignore that object next time.
In the Episodes, Barnacles can be poisoned by eating Poison Headcrabs or Antlion Workers. They will die shortly after eating these creatures. When they latch onto any type of Zombie, they will only consume the Headcrab, dropping the rest of the body.
 Related Achievements
|Barnacle Bowling (5G)|
|Kill five barnacles with one explosive barrel.|
 Behind the scenes
The Barnacle was designed by Ted Backman. It is described as a "steroid barnicle (sic) on crack" in the concept art. Although not seen in the game, the concept art shows that they have small feet to cling to ceilings. Within the game, it acts as a way to constrict the player's movement in dark areas. It was created to prevent experienced players from rushing through the levels, and make the player look upwards for the rest of the game once they encounter them for the first time.
They were originally intended to be able to grab objects like their Half-Life 2 counterpart. The player was able to trick the creatures and make them eat explosive materials such as crates of dynamite or propane tanks. They were originally had the ability to lower their tongue and grab their victim. In Day One, the unused Vortigaunt animations show the creature being grabbed and eaten by a Barnacle.
 Half-Life 2
Half-Life 2 version was by animated by Derek Jenson. The Citizens were originally intended to identify Barnacles and shout a warning to other nearby characters. In Episode One, Alyx Vance is able to identity and kill Barnacles. There was to be a variation of the creature called the Sand Barnacle.
In Online Gaming Review's early Half-Life Monster of the Week Feature preview, Barnacles were given the taxonomic designation "Cirripedia donaldsonia." This name is said to be derived from Dr. Louis Donaldson (a reference to Valve's former office manager), the discoverer and first victim of the creature. They are described as having a lifespan of 500 years, and infant, juvenile, and adult forms have all been observed. A Barnacle may tear free from its root attachment if it attempts to grab excessively heavy prey, leaving it grounded. These grounded specimens are said to be harmless as the adult forms of Barnacles lack any form of mobility. In this state, its base dries and hardens, and the creature eventually expires.
In some circumstances, the player can use the Barnacle's tongue to reach an upper area when being pulled up. In Half-Life, the player can use this method to reach chargers inside a silo in the chapter Blast Pit.
In an Ichthyosaur room.
 Opposing Force
 Blue Shift
 Half-Life 2
 List of appearances
 Main games
- Half-Life: Opposing Force
- Half-Life: Blue Shift
- Half-Life 2
- Half-Life 2: Episode One
- Half-Life 2: Episode Two
- Half-Life: Day One (First appearance)
- Half-Life: Uplink (Non-canonical appearance)
- Half-Life 2: Raising the Bar
- ↑ 1.0 1.1 1.2 Half-Life 2 Prima Guide
- ↑ 2.0 2.1 Half-Life 2: Raising the Bar, page 21
- ↑ Half-Life 2: Raising the Bar, page 14
- ↑ Interview with Gabe Newell on Gamereactor (May 12, 2004) (archived)
- ↑ IRC Interview on Far2Cool (October 17, 1997) (archived)
- ↑ Derek Jenson's personal website
- ↑ Half-Life 2 files (hl2/resource/closecaption_english.txt)
- ↑ Half-Life - Monster of the Week feature on Online Gaming Review (1997) (archived)