Vibroknife

A vibroknife, or vibro-knife, (PROSE: The Romance of Crime) was a weapon that consited of a vibrating knife activated by holding down a pressure sensitive trigger. (PROSE: Lucifer Rising)

Two men with vibroknives attacked the Sixth Doctor in an alleyway; he defended himself with his umbrella and was helped by a Whifferdill then known as Avan Tarklu. (COMIC: The Shape Shifter)

Jarrigan Voltt was framed for murdering Viktor Stott with a vibro-knife. (PROSE: The Romance of Crime)

Piper O'Rourke killed Federique Moshe-Rabaan with a precise incision to her heart and staged the death as a suicide by putting the vibroknife in her left hand. (PROSE: Lucifer Rising)

Roz Forrester had a scar on her left forearm from a vibroknife wound. (PROSE: The Also People) She was skilled a throwing her personal vibroknife; she hit Fenn Martle in his right eye. (PROSE: Original Sin, So Vile a Sin) Discovering he was taking bribes, she slit his throat with her vibroknife. (PROSE: The Also People)

The Seventh Doctor noted that it was important to carry a vibroknife on Scorbiski Major because there the fish go angle for the people on the shore with mooncalves as bait. (PROSE: The Also People)

A Megacity hovercab driver pulled a vibroknife on Chris Cwej when he refused to pay a triple fare. Chris took it from him and threatened him back. They compromised on a double fair and the driver let Chris keep the knife because he had plenty more. Upon seeing it, Roz noted how she didn't like vibroknives anymore. Chris had this knife confiscated after it was sensed by a weapon-detector. (PROSE: Shakedown) Chris later bought a vibroknife in Megacity. (PROSE: Mean Streets)

Crime lord Nastur liked using vibroknives on his victims, leaving them with vital parts missing. (PROSE: Mean Streets)

A public information poster at Roz's Adjudicator lodge had a faceless cartoon shadow holding a blood-stained vibroknife. The poster read: "STAY ALERT AT ALL TIMES. MOST MURDERS ARE COMMITTED BY SOMEONE YOU KNOW." (PROSE: Christmas on a Rational Planet)

Some children on Magellani Minimata carried junior vibroknives. (PROSE: Down)

Behind the scenes
Vibroknives are a common weapon in science fiction, most popularly Star Wars stories. Similarly-named vibroblade and vibraknife date back to 1940 and 1973, respectively.