Irken Technology
Maimbot
The Maimbot is an enormous Irken battle mech. It has a huge laser cannon attached to its left arm and appears to stand at least fifty feet tall. It was used by Zim to force a candy bar out of a non-compliant snack machine in Tak: The Hideous New Girl. The blast caused a blackout on an entire half of the planet Devastis. This blackout made Tak miss her initiation to be an Irken Invader, resulting in her trying to take over Earth instead. The Maimbot was never seen again, although Zim did request one in the episode Hobo 13.
The Massive
The Massive is the flagship of the Irken Armada and is their most powerful vessel. The Massive was designed and constructed by the Vortians, most notably Vortian prisoner 777, for Tallest Miyuki while they were allies. It is helmed by The Almighty Tallest from a central dais, surrounded by various crew members, all of which look the same. The insignia on the front is that of the Irken military and the pink stripe directly below that is the bridge. The Massive is surrounded at all times by an armada of smaller ships. The Massive travels around the universe to the planets conquered by the Irken Invaders to assist in the organic sweep, which is a process by which the planet is sanitized with so that "no Irken boot has to come in contact with any unsavory alien filth." This involves laser bombardment from a point in high orbit above the planet. Once the planet is swept, The Tallest assign it a purpose - which is usually whatever they randomly decide at the time--an episode where this is shown has them dedicating a recently-conquered planet entirely to parking space.
The Massive can be remotely controlled by a command console. This feature was exploited by Zim when he wanted to bring The Tallest to Earth to witness his latest plan for destroying it. During its flight at the hands of Zim, The Massive demonstrated its amazing strength, as it survived several direct collisions with various planets (also demonstrating the fact that it IS quite massive), and was even able to survive flight through the upper layers of a star. All the while, a Vortian ship helmed by a revolutionary force called The Resisty was attacking The Massive with lasers.
The Massive's armament, other than its accompanying armada, is a large pulse laser that emits from the bridge-cannon. The only reason that the Resisty's ship was not destroyed by this laser was because immediately before the shot, The Massive was turned around by Zim using the remote command console, causing the laser to miss. The only other seen weapon is the 'Organic Sweep Cannon', which shoots a blue 'Area of Effect' shot that radiates itself over whatever it hits, such as Blorch the Home of the Slaughtering Rat People. It presumably has other armaments, however none are ever seen.
In Dib's Wonderful Life of Doom, it is said that the side pods of The Massive are filled with Irken snacks, and that this is The Massive's weak spot. In the second-season episode Backseat Drivers from Beyond the Stars, Vortian Lard Nar also targets the "snack pods" of The Massive, intending to steal the Irken snacks to feed the growing anti-Irken resistance.
Megadoomer X-3 Stealth Mech
A view of the Megadoomer from the eponymous episode.The Megadoomer is a prototype assault robot. It was originally intended to be shipped to Invader Tenn on Planet Meekrob, but was instead shipped to Zim due to the "revolutionary" actions of a rebellious slave on the Conveyor-Belt Planet (detailed in Megadoomer). Zim was origanally intended to recive a number of dangerously maulfunctioning SIR units; these were sent to Invader Tenn instead. The major feature of its design, hence its title, is its ability to become invisible to the naked eye. It appears as though the mech was never properly tested before it was to be shipped to Tenn, because the Almighty Tallest probably wouldn't have sent it to her had they known its crippling, painfully ironic flaw: while cloaked, though the Megadoomer remains entirely transparent, its pilot sits completely visible. This is likely an intentional flaw by its creators, the Vortians, to weaken the Irken army.
Physical description
The Megadoomer is colored the dark reds and grays not uncommon to other Irken vehicles, and sports the one-eyed Irken symbol on its hull. It also walks on what GIR points out to be "chicken legs", not unlike many non-humanoid mechs such as those found in the Battletech universe. It appears to have no conventional windows, and is piloted by the use of levers. Tallest Purple's only reaction to the Megadoomer was that he "Didnt like it."
Onboard weapons
The Megadoomer is heavily armed, and its armaments include numerous artillery cannons as well as an excessively powerful weapon known only as the "Doom Cannon."
Stealth technology
As mentioned previously, when the Megadoomer's cloaking device is activated, the vehicle itself is turned invisible but the pilot is not, effectively rendering the entire cloaking system useless. Objects such as bushes and other debris getting stuck on the Megadoomer will also appear visible, which also make it trackable by the enemy.
An interesting note brought up in the commentary for the Megadoomer episode is that when Zim is in the Megadoomer's cockpit, he is lit by the cockpit's red lights and is colored red accordingly. However, when the mech turns invisible, Zim is colored in conventional night-time lighting. This discrepancy was refuted by the claim that the red lighting of the cockpit too becomes invisible, leaving Zim to be lit by what lights there are outside the vehicle. Oddly enough, Zim himself could still see the interior of the cockpit, even while in stealth mode.
Self-destruct
The Megadoomer is equipped with a self-destruct capability, presumably to destroy it if it were to be in danger of being captured by an enemy (or in the episode, photographed by Dib). The Megadoomer also ejects the pilot out of the rear of the ship and sends an automated message to the Massive before it self-destructs, informing the Tallest of its destruction.
Power draw
Throughout the episode the Megadoomer appears in, power supply problems present themselves constantly. When Zim and GIR unpack the mech, they find that batteries weren't included, forcing them to plug a massive power cable into conventional earth power outlets to sustain the mech's power draw. Though this solution allows for Zim's resultant impulsive rampage in the Megadoomer to continue, it proves to be far less practical than the batteries (which would have allowed the mech to remain self-contained, at least for some time) would have been; Every time the Megadoomer moves too far from the power outlet it relies on, Zim must summon GIR to locate another outlet closer to the mech.
This problem continues when Zim prepares the (unseen) Doom Cannon to kill Dib. The cannon requires so much energy to charge that it shuts down the entire city's electricity, and ends up never even being used.
Plasma-armed Battle Tank
The Plasma-armed Battle Tank was requested by Zim in the episode Hobo 13, along with a Maimbot, a Death Wave Cannon, some taquitoes, and a clown with no head for GIR. Not much is known about the Plasma-armed Battle Tank, though in the script for the unfinished episode The Trial, Zim mentions the fact that he piloted a "Spider/Crab Tank", and that may be the Plasma-armed Battle Tank.
Voot Cruiser or Voot runner
Zim's prized vehicle, the Voot Cruiser/Runner is Invader Zim's principle method of transportation, appearing in the majority of the show's episodes. Zim uses it to traverse distances great and small, whether moving from Earth to Mars or flying from his disguised base to a farm (both on Earth) with plans to poison cows with dookie (GIR Goes Crazy and Stuff). It is also sometimes referred to as the 'Voot Runner.' Unfortunately, like most Irken vehicles, the ship does not have the capability of going into hyperspace.
Though the Voot Cruiser seems to be equipped with a fair amount of features, no other Irken (nor any other alien species, for that matter) is ever seen using one. This would leave one to ponder whether the Voot Cruiser is an outdated or obsolete craft, perhaps a modern-but-low-quality one, or even a sort of custom craft assembled from assorted junkyard parts, much like Zim's own assistant GIR. This may be common practice, however, for in Tak: The Hideous New Girl, Tak uses a ship that is also never seen in use by any other, except Dib after Gaz repairs Tak's ship. In fact, she claimed to have built it herself. Tak's ship resembles an Irken Spittle Runner, so it is possible that she constructed her ship from a Spittle Runner wreck she found on Dirt, the planet she was banished to janitorial duty on.
Despite its uncommonness made apparent from episode to episode, on this basis it also proves a definite usefulness even in the incompetent Zim's hands. In the first episode of the series, The Nightmare Begins, the Voot is able to transport Zim from the planet Conventia to Earth (a considerable distance), though taking the whole of 6 months, without trouble (other than GIR singing the whole time).
In addition to the agreeably reliable though somewhat standard space and atmospheric travel abilities, the Voot Cruiser also carries dual energy pods which can separate from the Cruiser, fly independently at large distances from it, and reattach to continue powering the Cruiser (as seen in the episode Planet Jackers). These pods can be seen in the above screen-shot as the large purple devices toward the top of the Cruiser. The Voot employs G-Force compensators to dampen turbulences otherwise to be felt at extreme speeds or maneuvers, and its spherical canopy appears to be made of a material that can withstand tremendous impact and contortion, then with the press of a repair button regain its original shape (the Voot on a whole, however, seems peculiarly vulnerable to physical contact with earthbound bees). The canopy itself opens upward to allow entrance and exit into the cockpit. The Voot Cruiser also contains a holographic projection system and an onboard computer. The main form of combat for the Voot seems to be ramming other ships, as seen in Tak: The Hideous New Girl (though this may simply be Zim's impulsiveness shining through; the ship is equipped with dual laser cannons that he briefly used in the same episode). The Voot also has a rear loading cargo bay for supplies(as seen in The Girl Who Cried Gnome).
In the episode Hamstergeddon, as pointed out by the commentary, the ship Zim is using to battle Ultra Peepi is actually not the Voot Cruiser, but a similar looking ship. It is more streamlined when compared to the regular Voot Cruiser.
Transport Station
This ship is seen in the episode 'Bloaty's Pizza Hog'. When Gaz has to save Dib, she Teleports her way on board. Zim was keeping Dib in his Containment Chamber which is penetrable by Gaz's foot.
It is also seen in the episode Future Dib when Zim positions it so he is safely orbiting earth out of the blast radius of P.E.G (Perpetual Energy Generator).
Transport Station Escape Pods In the episode 'Bloaty's Pizza Hog' Gaz escapes Zim's Transport station in these trianglular ships. Weapons include Laser Turret and Attachable Claw. It also has a videophone on board which Gaz uses to contact Professor Membrane.
Other vehicles seen
The Spittle Runner,
smallest and most common unit of the Irken Armada.
The Shuvver,
the 2nd most common unit. Are seen blasting an Irken Invader symbol into the face of the planet Blorch
The rarely seen but powerful
Ring Cutter.
The Ripper.
The first ship to be seen in the show when the camera zooms out of a cockpit in 'The Nightmare Begins'
Viral Tank,
the largest ship in the Armada, save for the Massive, seen in the opening credits. It's large size can be seen when Zim's Voot Cruiser flies over one in the opening credits
Experments
The various monsters created throught genetic mutations