After an expedition force of Xiliens landed on Earth, they requested that two of Earth's resident Kaiju, Godzilla and Rodan be used by their kind to defeat King Ghidorah on Planet X. After the humans obliged, two Xilien UFOs used their tractor beams to fly Godzilla and Rodan to the neighbouring planet. Later, the UFOs return to Earth, but wer now carrying Godzilla and Rodan under mind-control. As the monsters raged, now allied with Ghidorah, A fleet of UFOs arrived and began to destroy buildings with their laser beams. Eventually, the humans broke the mind-control over the two heroic kaiju, who then proceeded to repel Ghidorah once again, whilst the A-Cycle Light Ray Guns were used to destroy the UFOs, ending the invasion once and for all.
- Xilien UFOs are able to fly at speeds approaching 1 tenth of the speed of light (67,061,662.9 meters per second).
- Each UFO can fire a powerful energy ray.
- The Xilien UFOs can utilize tractor beams to lift and transport large objects or kaiju, which can easily be restrained by becoming placed in a form of suspended or altered animation by the beam itself.
- The Xilien UFO is the first Alien Spacecraft to be seen in a Godzilla film, and the third Alien Spacecraft to be introduced overall, after the Mysterian UFO and Space Station.
- The familiar, synthetic sound that was made by Toho to represent the UFOs' engines has since been used in many different films and television series, most notably in the Ultraman series.