Weapon (The Eyeless)
The weapon was an unnamed superweapon used to wipe out Seventh Galaxy in the Last Battle of the Seventh Galaxy. It was housed in the Fortress on Arcopolis until the Tenth Doctor destroyed it (PROSE: The Eyeless). It was created by an unnamed group of people who, at the time The Eyeless took place, were all dead and their planet destroyed (PROSE: The Eyeless, p. 77).
Appearance
To human eyes, the weapon appeared to be a cylinder made of burnished metal, about a metre long and ten centimetres wide, and had no obvious controls or symbols. It was stated that "more interesting things" were going on in the higher, lower, and sideways dimensions (PROSE: The Eyeless, p. 196). The Tenth Doctor described the energy inside the weapon as a "trapped perpetual lightning bolt" and "so dark it would blind anyone who looked at it" (PROSE: The Eyeless, p. 196).
Abilities
The Tenth Doctor stated the weapon was able to destroy not only a civilisation, but all traces of them, anything they'd seen — including stars — and all who remembered them. It would go on to do the same to those who remembered them and was able to wipe out an entire galaxy (PROSE: The Eyeless, p. 80). He went on to state that the weapon worked using quantum physics, the observer effect, the superforce, vunkotechnology, and vundatechnology (PROSE: The Eyeless, p. 80). The weapon was activated by touch and handling it with gloves would keep it going off (PROSE: The Eyeless, p. 196). The Doctor theorised that there was a protective field around the weapon which inadvertently kept the survivors on Arcopolis alive (PROSE: The Eyeless, p. 82).
Although the weapon destroyed its victims utterly, destroying matter and energy so completely was impossible, and it left what the Doctor described as a "complicated blast shadow," which were the ghosts haunting Arcopolis (PROSE: The Eyeless, p. 208). As the ghosts were holes in reality, anything they touched would fall out the universe (PROSE: The Eyeless, p. 209).
History
The weapon was fired in the year Battle of the Seventh Galaxy, killing so many that the casualties of Arcopolis were negligible (PROSE: The Eyeless, p. 82). Fifteen years after, the Tenth Doctor came to Arcopolis to take destroy the weapon. The Tenth Doctor fired the weapon and killed all of the Eyeless, however it malfunctioned and did not kill anyone else (PROSE: The Eyeless, pp. 215, 219).