|This article would greatly benefit from the addition of one or more new images.|
Insect worker caste
The Antlion Worker, also known by Vortigaunts as the Acid-lion, is an Antlion subspecies only found in or near the larval chambers, where it performs various tasks including the tending of Antlion Grubs. Workers produce a corrosive and poisonous acid which they use to create tunnels for the nest as well as to ward off attackers.
The Worker is a luminous animal with ant-like features, such as a pair of transparent wings which it uses to fly over short distances, big head with antennae, and less-developed mandibles.
 Behavior and skills
Antlion Workers primarily attack by hurling a devastating poisonous spittle, a mixture of secretions and bile, at foes from a distance with great accuracy and extreme speed, similar to Bullsquids. If caught up close, they attack with their claws, though they usually prefer to use their more powerful ranged attack and often retreat if their attacker gets too close. These factors combine to make the Antlion worker an uncommonly standoffish foe.
When killed, Antlion Workers explode in a shower of acid inflicting considerable splash damage on anything within range.
Antlion Workers are stronger than normal Antlions, and, due to their highly effective ranged attacks, they are also more versatile. Closing up with one has one advantage, but two disadvantages.
Assaulting a Worker up close can be a viable strategy in some situations because the Antlion prefers not to attack with its claws, since this is not particularly effective, and it usually tries to retreat instead, giving a chance to be chewed up with the Submachine Gun or the shotgun. On the other hand, if the distance is not closed fast enough, and the Worker has time to use its ranged attack, there is less time to dodge the projectile than from far away. In addition, one should remember that when the worker dies, it showers everything nearby in acid.
Alternatively, it is also a good strategy to keep a distance and engage with a range weapon, such as the .357 Magnum. Workers skitter around a fair bit, but stop moving to use their ranged attack, giving enough time to score a hit and dodge their attack. A Worker should go down with one or two Magnum hits, depending on the difficulty level.
Just like regular Antlions, Workers can be flipped over with the Gravity Gun, exposing their more vulnerable undersides.
The only way to kill an Antlion Worker without having it explode is to lure it into deep water, causing it to drown.
Alternatively, it can be leaded into the tongue of a Barnacle. However, when the stationary alien bites into a Worker, the Antlion will explode, killing everything nearby.
 Related Achievements
|Half-Life 2: Episode Two|
|Acid Reflex (5G)|
|Kill an acid Antlion Worker.|
 Behind the scenes
According to Joshua Weier, the Antlion experience in Half-Life 2 was characterized by a mindless, constant onslaught of bugs rushing the player's way. Valve devised the Antlion Worker for Episode Two, as a way to add depth and variety to the underground sequences, by leveraging new types of gameplay. Unlike normal Antlions, the Worker chooses to avoid direct confrontation, skulking in the background and lobbing acidic globs from a distance, what extends the amount of time players spend with each creature. By contrast, an encounter with an ordinary Antlion is over in seconds. The spitting behavior was derived from the Bullsquid of Half-Life, but was updated to fit the more physical world of Half-Life 2. To that end, the spit globs are not merely sprites, but physically simulated objects, flying through the air along realistic trajectories.
According to The Orange Box Prima Guide, Worker Antlions are a subgenus and a genetic mutation of the Antlion, and they are rumored to have burrowed near the many toxic waste dumps scattered around the countryside, hence their unique appearance. Marc Laidlaw debunked these claims, saying he's "not sure where that info comes from but it sounds improvised. I don't recall anyone on the team thinking of the creatures that way, but it's possible someone told that to the Prima writer off the cuff."
 List of appearances
- Half-Life 2: Episode Two Teaser 2 (First appearance) (Non-canonical appearance)
- Half-Life 2: Episode Two
|Castes||Antlion Grub · Antlion Guard · Antlion Guardian · Antlion Soldier · Antlion Worker|
|Other||Antlion Detector · Pheropods · Restrictor · Victory Mine|
|Castes (cut)||Antlion King|