Quote Originally Posted by Omanes Alexandrapolites
Hi King Jan III Sobieski,
I'm not too sure either, but I believe that it is related to FPS (First Person Shooter) games. Instagib, in such games, is a deadly weapon which kills the victim instantaneously, regardless of range, with one simple and rapid shot. I'm not certain if this is related though, so you may have to wait for a member of staff to confirm. Sorry.
Correct, its taken from a mod in Quake (2 or 3) and Unreal Tournament series.