The Hydralisk serves its role as an all purpose fighter. It has a powerful attack but its survivability is pretty weak making them more effective on the offensive. The Hydralisk will also use a melee attack animation if a target gets to close, which still does normal weapon damage.
This ability is available to several Zerg grounds units including the Hydralisk. A burrowed unit will dig itself into the ground rendering it invisible and cannot be attacked unless a nearby detector unit can spot its location. The burrowed unit cannot attack any units, but it can see a very small distance. This ability is great for hiding your injured units to allow them to recover health or for spying at certain locations, such as expansion points or outside enemy bases to track enemy movement.
The peaceful herbivore herds of slothien were assimilated into the zerg Swarm to produce one of the fiercest and most diabolical of the zerg strains. The evolutionary matrix of the caterpillar-like slothien was supercharged by the Overmind, twisting the hapless creatures into the nightmarish killers known as hydralisks. These once mild creatures now hunger for blood and violence, and they are infamous for acting in a particularly savage fashion.
The spindly, snake-like hydralisks house hundreds of armor-piercing spines within their upper carapace plates. These spines have been specifically evolved from the defensive urticating hairs of the slothien and adapted to a new purpose. Hydralisks use powerful muscle contractions to launch the spines in volleys at enemies approaching from either the air or the ground.
Hydralisks are especially fond of lying in wait for their prey. Groups of them have been observed burrowing into the ground in the pathway of civilian workers, uncovering themselves when they sense an opponent is near. Ambushing from burrowed positions is a favored hydralisk battle tactic, with hydralisks showing a preference for waiting until an enemy has passed before emerging to attack, or boxing in a group of enemies to destroy them with a deadly crossfire.
Thanks to the remarkable musculature of a hydralisk (4,000 muscles compared to a terran's 629), the penetrative force delivered by a hydralisk spine is quite astounding. A single spine can easily penetrate 2 cm of solid neosteel even at maximum range. Under any circumstances, massed groups of hydralisks should be approached with extreme caution and preferably siege tank support.
