Sonic blaster

A sonic blaster was type of weapon popular by the 51st century. They were produced at the Villengard factory. They were seen used by Professor River Song and by Captain Jack Harkness, who brought one with him to the year 1941 during his conning days.

The Doctor switched Jack's sonic blaster with a banana at one point. (DW: The Doctor Dances)

Abilities
The blaster used a sonic wave projected into the form of pulsing squares of blue light which could cut through thick walls, and also had a reverse function which could replace the removed chunk of material afterwards. This was deemed a "special feature" of the blaster and it was said to use up a lot of the batteries on which it ran. (DW: The Doctor Dances)


 * Jack explained that the blaster used digital technology, so by implication, the blaster might encode the molecules of the destroyed materials and re-integrate them from the same source.

In the hands of the Doctor and his friends, the blaster was never seen to have been used as an offensive weapon, but rather as a tool. Although Jack brandished the gun towards those infected with Empty Child and explained that the blaster could also function as a sonic disruptor and a sonic cannon, it was only ever known to have been used as a means of escape or forced entry. Jack used it to open a door by removing the lock and Rose used it to create a hole in a floor, but notably not injuring her, Jack's or the Doctor's feet in the process. The Doctor used it to blast away part of the wall to escape the gas mask zombies, just as he and River Song later used to create holes in the wall and floor to escape from the Vashta Nerada. (DW: The Doctor Dances, Silence in the Library / Forest of the Dead)

Behind the scenes

 * Production staff referred to this weapon as the "squareness gun" before the Doctor called it by that name.
 * Steven Moffat has suggested that River's gun might be the same one Jack used, as he apparently left it in the TARDIS when he parted ways with the Doctor. (Doctor Who Confidential) This was also stated in IDW: Tesseract, but over time the handle had changed from a dark brown to an ivory colour. (DW: The Doctor Dances, Forest of the Dead)