Tantalus rays, more properly known as X-14 Tantalus Rays, are the main weapon of the Vorticon Mothership. There are eight of them, dispersed around various places on the mothership.
The rays are housed inside areas known as Tantalus Centers. Inside the centers, there is a special room, the Tantalus Control Room, where the ray itself resides. These rooms have a very similar design, all of them having stairs leading up to the rays. Above each ray, there is a sign in the Standard Galactic Alphabet saying "TANTALUS", followed by the name of the city the ray is aiming at.
The Tantalus rays are powered by cells from the Big Purple Space Amoeba; one of which sits at the top of every Tantalus ray, with two Jacob's Ladders around it. The ray itself is a large rectangular block-like mass with one activation switch (with a sign with "ON" written in SGA), a visual screen and a plasma reactor. The reactor sends its power to the front of the Mothership via a long power cable that can be seen to run from underneath it, deep into the Mothership.
The rays are easy enough to operate, and in Keen 2 they have been pre-aimed at various important Earth cities. All that is required to turn them on is a simple flick of the activation switch; this can be done accidentally, as there are no security precautions in place to prevent premature or accidental firing.
The Tantalus rays are also rather fragile, the single amoeba cell being their only (but significant) weak spot. A single shot is sufficient to destroy it, sending a pulse of energy through the entire system. This disrupts not only the Tantalus ray itself, but also all the electronics concerned with it. This can be seen as the visual screen goes blank when the ray is damaged. (This act gains Keen 10,000 points.)
When fired simultaneously, the separate blasts from each ray are directed to a firing bay at the head of the ship, which will then emit a blast of green energy of tremendous power which will stream toward its target at roughly twice the speed of sound. A single blast can destroy a planet, but all eight blasts simultaneously are probably needed to ensure total atomization of the target. If one or more of the rays is fired prematurely then the target will be fragmented, and these fragments pose a severe hazard to the Mothership, which must remain in orbit around its target.
The Tantalus rays exist for the singular purpose of destroying Earth. The Vorticons' leader, the Grand Intellect, has commanded them to destroy Earth, and is controlling them to make sure they do so. Each Tantalus ray is aimed at a separate prominent Earth city. As mentioned earlier, this is unnecessary, so the choice of targets suggests a more personal or political take on the mission.
The "final" or most prominent ray is aimed at Washington D.C.; it is located in the nose of the ship, closest to the firing bay. Also, the United States is the only country with two cities as targets. This suggests either an American centered perspective, or anti-American bias on the part of the Vorticons and the Grand Intellect.
Each ray is aimed at a specific Earth city. In each of the visual screens, a famous building in or near that city is shown, probably indicating the exact point where the ray will hit.
The cities targeted (and the structures shown on the screens) by the eight rays are as follows:
- Washington DC (USA) – the Capitol – Washington Tantalus Center
- Moscow (Russia) – Saint Basil's Cathedral in the Red Square – Moscow Tantalus Center
- Paris (France) – the Eiffel Tower – Paris Tantalus Center
- London (England) – the Big Ben – London Tantalus Center
- Cairo (Egypt) – Great Sphinx of Giza – Cairo Tantalus Center
- Sydney (Australia) – Sydney Opera House – Sydney Tantalus Center
- New York (USA) – the Statue of Liberty – New York Tantalus Center
- Rome (Italy) – the Colosseum – Rome Tantalus Center