Corbomite - Nonexistent substance featured on episode No. 3 "The Corbomite Maneuver" on the sci-fi adventure STAR TREK/NBC/1966-69. When an alien being captured the starship USS Enterprise, Captain James T. Kirk (William Shatner)  - in an attempt to call a bluff - informed the hostile alien that the hull of his spacecraft contained a material called Corbomite. If the ship was attacked it would release a destructive force that would destroy the attacker. An excerpt from the script follows:  

Kirk:	This is the Captain of the Enterprise. Our respect for other life forms requires that we give you this...warning. There is one critical item of information that has never been incorporated into the memory banks of any Earth ship. Since the early years of space exploration, Earth           vessels have had incorporated into them a substance known as...Corbomite. It is a material and a device which prevents attack on us. If any destructive energy touches our vessel, a reverse reaction of equal strength is created, destroying...
Balok:	[Deep male voice interrupts] You now have two minutes.
Kirk:	DESTROYING the attacker. It may interest you to know that since the initial use of Corbomite more than two of our centuries ago, no attacking vessel has survived the attempt. Death has...little meaning to us. If it has none to you then attack us now. We grow annoyed at your foolishness.

This same ploy worked against the Romulans in the Romulan Neutral Zone on episode No. 40 "The Deadly Years" when Kirk claimed to have a "Corbomite device" which would wreak havoc over a 200,000 kilometer radius if his ship was fired upon.