X-tonic rays were a form of radiation that emanated from X-tonic stars. Professor Hobbes averred that such rays could also be thought of as "raw galvanic radiation".

He further claimed that this radiation was so deadly to living things that there "couldn't be" life in the star system that included the planet Midnight. Shielding from the radiation was possible though, even by glass. For example, Finitoglass could stand the radiation for several minutes, and the Leisure Palace had large domes fifteen feet thick for more effective shielding.

Hobbes' assertions, though generally correct, were too absolute for the Tenth Doctor's liking. Indeed, at least one being, the so-called "Midnight entity", was able to live and apparently thrive on the surface of the X-tonically-bombarded planet. (TV: Midnight)

In 2023, UNIT HQ in London had a galvanic beam at their disposal, a large energy weapon which could be used to destroy satellites. It produced a highly focused charged laser which could supposedly zero in on a pebble on the Moon from Earth. The Fourteenth Doctor was forced to regenerate after being assaulted with the galvonic beam in the chest by the Toymaker. (TV: The Giggle)