Baneling

The baneling is a wheel-shaped explosive zerg strain in StarCraft II.

Overview
Banelings are created from zerglings following a brief chrysalis phase. In the new form, the zergling's claws shrivel and become withered, and a swollen sac filled with volatile chemicals grows out of its back.

Banelings can waddle, but after an evolution they can tuck into a tight ball and roll around the battlefield.

The creature's only form of attack is to trigger a reaction within its chemical payload that causes it to explode with devastating force and shower the immediate surroundings with searing acid.

These living bombs are highly effective against both structures and ground forces; in fact, a clutch of them is capable of wiping out a group of vehicles and infantry in the blink of an eye. The banelings' lethality is further enhanced by the zerg predilection for burrowing. An apparently safe area can soon turn into a deathtrap as these monstrosities emerge and roll into the midst of their foes, giving them virtually no time to react.

History
The baneling is descended from the zergling during the four years following the Brood War, created through the advanced ability of the zerg queens to manipulate their offspring. The queens have engineered a morph that can contain its energies until just the right moment.

Upon its first appearance on the battlefield, the baneling was mistaken for a zerg mutation of an unspecified genus before the truth became known. Terran commanders now train their troops to watch for these abominations. In the meantime, scientists are desperately trying to develop chemical rounds that will cause banelings to detonate before they reach terran lines.

Game Unit
Banelings are relatively large units that slowly move around the battlefield and kill opponents with a low-damage suicide attack.

As of April 2009, banelings do not roll unless they have their speed upgrade.

Banelings "stand still" when idle.

Attacks
Banelings are strong against melee units and "light" buildings such as bunkers and photon cannons but are weak against ranged weapons due to their low hit points. They are designed to counter zealots, zerglings and unupgraded marines.

The baneling's splash attack does not currently injure friendly units. It does full damage within the splash radius.

Banelings only explode as part of an attack, or when destroyed. They can be commanded to explode while burrowed, like a mine.

Banelings won't accidentally target buildings when ordered to attack units instead. To destroy buildings, they must be manually targeted against them.

Strategies
Banelings are a powerful economy-raiding force; by using overlords to transport them into an enemy base, they can quickly devastate the workers. However, a planetary fortress is well suited to destroying the banelings. Use of raiding is recommended even until late game.

Banelings should be mixed with zerglings when facing ranged opponents because they become difficult to focus fire; even one baneling escaping the fire can destroy a mass of ranged units.

Banelings have low hit points so are best used in ambushes. They can burrow, attacking like mines, but can also attack from other hidden areas, such as behind trees, to accomplish the ambush.

Banelings are very useful against marines and zealots, even into the late game, and generally dominate units such as zerglings in combat, but zerglings can come out ahead with micro.

As they do splash damage, banelings are effective against cloaked units. For instance, a group of dark templar attacking a hatchery can be eliminated by banelings that target the hatchery itself.

A baneling/roach combo can be very powerful against terrans. The roaches will soak incoming damage, making it easier for the banelings to reach their targets.

Baneling Development
As of April 2008, banelings have been increased in size from previous builds to make it easier to focus fire on them. In addition their splash radius was increased.