A species of subterranean Kaiju that was controlled by the Vicious Underground Phantoms and Subterrans. They aspired to enslave the entire human race living above-ground and sent Telesdon as the first stage of their plan to overthrow the surface. Telesdon is able to move freely underground by digging with its pointed, shovel-like nose and attacks enemies by spitting a deadly stream of flames from its mouth.

A woman of the Subterrans uses a Keritium Magnetic Light Wave to disrupt electronic and magnetic devices throughout Tokyo. She then calls upon Telesdon and it appears near the Tokyo TV Center. The SSSP attack Telesdon with Napalm bombs to no effect, and it starts attacking the nearby cities at night, destroying highways and skyscrapers with its fire attacks and its superior size.

Ultraman appears after defeating the Subterrans. Telesdon tries to wrestle Ultraman to the ground to no avail as Ultraman finishes it using his Ultra Back Throw and Boulder Toss.