Ultralisk

The Ultralisk is a relatively high-level ground unit in the 1998 Blizzard Entertainment RTS (real-time strategy) game StarCraft. While it is one of the most expensive Zerg units, it is also the most powerful, in terms of brute power combined with its sheer mass and endurance. With a base 2 armor and 400 hit points, the Ultralisk is one of the toughest enemies to kill when fully upgraded, making it a favorite target of spells such as "Spawn Broodling" (a one-hit-kill to any biological unit) and "Psionic Storm." Its primary weakness is a weak attack - while it has a high rate of fire, it does little damage and takes time to switch targets. For such a large unit, it is suprisingly fast, especially after upgrading its speed. It also has the destinction of being one of the few Zerg ground units that is unable to burrow underground, presumably because of it's massive girth. (Broodlings and some heroic Zerg ground units also cannot burrow.) Unlike other Zerg units, Ultralisks take a lot of "Control" to produce.

The Ultralisk is armed with a pair of "Kaiser blades", which are rumored to be monomolecular in nature and nearly indestructible.

One of the most effective strategies for using Ultralisks is to plant them in the middle of an army of much weaker units. By doing this, it is specifically targeted by the majority of the opposing force, allowing it to take the brunt of the damage, while your real core army attacks without being harmed.

Ultralisks can only be produced after the player morphs an Ultralisk's Den. They have special upgrades available in StarCraft: Brood War which enhance their speed and armor, in addition to the typical armor upgrades available to all Zerg units. These special modifications came about due to direct exposure to raw Vespene gas.

The Ultralisk is descended from the peaceful Brontolith. The current Ultralisk bears little resemblence to the original creature. An Ultralisk is about 20 meters long (the size of a city bus), according to StarCraft: Alternity.

The Ultralisk was first observed by Terran forces when a small number destroyed a Terran Confederacy outpost on Timul IV.

The Torrasque
The Torrasque is an especially powerful hero Ultralisk. The Torrasque has double the hit points and does over twice as much damage as a typical Ultralisk. The name is derived from the Tarrasque, a powerful mythological monster (and one which can regenerate from apparent destruction in its Dungeons & Dragons incarnation). The Torrasque is present in some campaign missions but is absent in official multiplayer games.

Enslavers
It is first introduced in StarCraft: Enslavers on Aiur. Part of a Brood under the control of a Cerebrate controlled by Alan Schezar's Ghosts using Khaydarin Crystals and ancient Protoss technology.

When a former Alpha Squadron commander teamed up with Mojo, a Protoss Praetor, to attack Schezar's Scavengers, they were attacked by a strangely powerful Ultralisk. Mojo feared it was the Torrasque, a creature which had slain many Protoss.

It rampaged through their base before it was finally brought down by sustained offensive fire. The Terrans were surprised when it spontaneously regenerated after a few minutes.

A former Alpha Squadron advisor, Magellan, noted that it had a genetic signature very similar to that of the Cerebrate. Mojo theorized that slaying the Cerebrate would prevent the resurrection of the Torrasque.

Mojo was right. The Zerg Overmind was dead, so slaying the Cerebrate prevented its own resurrection.

Episode V
When the United Earth Directorate activated the Psi Disruptor and attacked the Zerg on Char, the second Zerg Overmind was defended by three Zerg Cerebrates.

One was surrounded by Ultralisk caverns, and could create the powerful Torrasque. Once again, the Cerebrate could resurrect the Torrasque upon its death. The Psi Disruptor, however, prevented the Zerg Overmind from resurrecting its Cerebrates. With great effort, the UED forces repeatedly slew the Torrasque before destroying the Cerebrate.

Episode VI
When Infested Kerrigan allied with Jim Raynor, Fenix and Arcturus Mengsk to fight the UED, they decided to attack the Psi Disruptor.

Jim Raynor disabled the Disruptor by destroying its fusion reactors, and then Mengsk send down a SCV, carrying a psi-emitter, to lure nearby Zerg. These Zerg would then fall under the command of Infested Kerrigan.

The SCV encountered the Torrasque, which were added to Kerrigan's forces.

Resurrection IV
Four Torrasques were observed bursting from cocoons on Braxis in the StarCraft mission, Resurrection IV, when Jim Raynor and Taldarin attacked the resurrected Infested Stukov in an attempt to rescue him from his infection.