You shot me in the back!
The Operative uses this weapon, which fires nonlethal purple energy bolts, in his unsuccessful attempt to stop Mal from broadcasting details of Alliance crimes against the planet Miranda throughout the Verse.
Chrome-plated static solid cast resin prop, used as a hero with superimposed CGI; the offset seam line on the front of this prop is clearly visible onscreen in the split second closeup shot.
From the Prop Store of London.