I guarantee you've never heard of it because it only appears in a series of novels by Steve Perry, the Matador books.
The gag is, it glues to the back of your hand. The barrel runs along your index finger, and you fire it by pointing your finger and touching the barrel tip with your fingernail.
It fires microdarts which can have a variety of effects, the #1 use being a drug called "Spasm" which makes every muscle in the body contract involuntarily, leaving the victim tied in a knot for 6 months.
The original trilogy of books:
The Man Who Never Missed
Matadora
The Machiavelli Interface