Scourge

The scourge is an aerial zerg kamikaze strain.

Overview
Scourges are blind, suicidal fliers of unknown origin, seeking out enemy starships and diving into them. Catalytic agents within the Scourge allow it to undergo a form of plasma metamorphosis, causing it to explode like a living bomb. A single scourge is capable of destroying a terran starfighter or shuttle and a handful can breach the hull of a starship. They are able to engage these targets in both air and the vacuum of space.

The primary drawback of the scourge is its limited ability to store energy, able to fly for barely a few hours without requiring additional substance. To conserve energy, they often perch on the backs of overlords. However, this presents a hazard, as the scourge's explosive nature can damage friendly zerg at this proximity.

Scourges possess a simple genetic makeup, allowing them to spawn in pairs from a single larva similar to that of zerglings. By the Second Great War, scourges could be spawned from leviathans.

StarCraft
Scourges spawn in pairs. Patrolling scourges may help deter low intensity enemy drops. Without supervision groups of scourges tend to lock onto and attack the first target that comes into range which may be overkill against low-HP targets (causing scourges to sacrifice themselves needlessly). Using other units to draw enemy fire may allow scourge to hit.

Corsairs may be micromanaged to negate attacking scourge. If the corsairs are not managed so expertly, armor upgrades may be beneficial for scourges.

If a scourge egg is hatched after the controlling player is eliminated, one will spawn normally but the other will become blue and neutral.

Development
Originally, scourges were called "avengers." Instead of being produced at a hatchery, they spawned from destroyed guardians.

StarCraft II
Although absent from multiplayer, scourges are present in StarCraft II: Wings of Liberty, though mainly to provide ambience. They are seen as early as the protoss mini-campaign, and a number appear on Char in its defense. They are last seen as a special form of attack by leviathans, dealing 500 damage each.