Siege tank

The Siege Tank is a Terran artillery unit found in the real-time strategy game StarCraft. It is commonly used to hold ground, either for defensive or offensive purposes.

Background
The AAV-5 Arclite Siege Tank is known for its powerful 80 mm PPG-7 plasma cannons, and must deploy into a stabilized siege mode before using its 120 mm Mjolnir Artillery Cannon. The tank has a crew of three: gunner, driver, and commander/navigator.

Originally, the Siege Tank was meant to serve as an immobile defense cannon. Once the Guild Wars erupted and the Goliath showed how powerful mobility is in the field, the Siege Tanks were upgraded. The first Siege tanks were of the original defense cannons that had been modified, but they were later manufactured to be mobile from the start. The final, modern form of the Siege Tank is a dual-mode vehicle.

Game unit
The Siege Tank is produced at a Factory, for a cost of 150 Minerals and 100 gas. It has 150 hit points and 1 point of armor. In tank mode, it deals 30 points of explosive damage; in siege mode (researched at a Machine Shop attached to a Terran Factory), it deals 70 points of explosive damage. The tank is far more powerful, but cannot move or enter a Dropship, while in siege mode.

The explosive attacks deal splash damage to both friendly and enemy units, and have a minimum firing range while in siege mode, allowing melee units to easily attack the Siege Tank once they get close enough. Two Siege Tanks may inadvertently damage each other while attempting to attack melee units near other tanks.

In siege mode, the tank has an extremely long firing range which extends beyond its own vision range. Marines, Ghosts, and Wraiths are useful as spotters -- in dire situations, a Terran player could even lift off one of their buildings for use as a spotter. Use of spotting can allow the Siege Tank to destroy defensive structures with ease.

Some players prefer to "wall-in" their Siege Tanks, by erecting buildings to surround the tank, thereby protecting it from melee attack.

Siege Tech
Allows Siege Tank to deploy into Siege Mode.
 * Cost: 150\150
 * Researched at: Machine Shop

Upgrades

 * Vehicle Weapons
 * Vehicle Plating

Counters and Weaknesses

 * Melee units can easily kill a Siege Tank without fear of counter-attack: in particular, Zerglings and Zealot can easily destroy a Siege Tank. The transition from tank mode to siege mode takes several seconds, during which time the tank will be both defenseless and immobile.
 * The Corsair's Disruption Web prevents the tank from firing, forcing its commander to waste valuable time switching to tank mode, moving from under the web, and switching back to siege mode.
 * Enemy Terran Ghosts can use Lockdown to immobilize the tank.
 * Zerg Queens can use Spawn Broodlings to instantly kill the tank.
 * A tank in siege mode deals splash damage to friendly units and structures nearby its intended target. If 2 Siege Tanks are in range of each other, 1 tank under attack by melee units may be destroyed by its brother tank if it fires.
 * The Siege Tank cannot attack air units.
 * Both modes of the Siege Tank deal explosive damage. Thus they do only 50% damage against small units, and are entirely ineffective against Protoss Zealots unless deployed in groups.
 * The Arclite Shock Cannon is slow to fire, roughly once every five seconds.

Tactics

 * The Siege Tank is often accompanied by the Goliath. The Goliath ground-to-air attack has a significant range, and deals 32 damage when fully upgraded.
 * Placing a Siege Tank with Bunkers full of Marines also helps defend the tank.
 * Most beneficial is to place the Siege Tank on high ground for added protection against ground forces. All the melee units in the game are biological, so a smart Terran commander will have a Science Vessel use Irradiate on the tank. Any biological enemies around the Tank will take damage and eventually die, while the Tank remains unharmed (Irradiate only harms biological units, while the Tank is mechanical). The Science Vessel can also use Defense Matrix on the Tank, granting it an extra 250 HP while other forces are called in to protect it.
 * In allied games, the Zerg Defiler's Dark Swarm protects the Siege Tank from all long-ranged fire (in effect, from all air-to-ground attacks).
 * Terran Firebats can use their melee attack to help protect the tank. As a bonus, the Firebat deals concussive damage, so small units that would only receive half the damage from the Siege Tank's attack receive full damage from the Firebat, and vice-versa.
 * A tank is often the best way to take out a cloaked Ghost that has painted a target for a nuclear launch close by. If a detector unit or comsat station is available the tank can kill the ghost because of its greater range.
 * An effective way to destroy an opponents base or units is to first camp your tanks outside of your opponent's sight range in siege mode and comsat the area you would like to attack. Since tanks in siege mode have a longer attack range than their sight range, comsatting the area will maximize their attack, while at the same time reducing the chances of counter attack. You can then proceed to tank push farther into his base.

Quotes
The Siege Tank has many stereotypical, military quotes. The driver of the tank is seen as a large man in body armor who speaks in army lingo. Several of his quotes are obvious taken from the classic Vietnam War films Full Metal Jacket and Apocalypse Now. See Starcraft Quotes.

Additional
The Mjolnir cannon that the tank is likely a reference to the hammer of the Norse god of thunder, Thor.