the scope of their employment, and others. Where the actor is present, there is always the possibility he will realize that deadly force is not necessary, but deadly mechanical devices are without mercy or discretion. Such devices are silent instrumentalities of death. They deal death and destruction to the innocent as well as the criminal intruder without the slightest warning. The taking of human life [or infliction of great bodily injury] by such means is brutally savage and inhuman. Computer viruses Many computer viruses take the form of booby traps in that they are triggered when an unsuspecting user performs an apparently ordinary action such as opening an email attachment. Practical jokes Instead of being used to kill, maim or injure people, booby traps can also be used for entertainment. Practical joke booby traps are typically disguised as everyday items such as cigars or packets of chewing gum, nuts or other snack items. When the victims attempts to use the item, the trap is triggered. Two of the best known examples of this are the exploding cigar and dribble glass; others include the Snake Nut Can and shocking gum. Booby traps can also be constructed out of household or workplace items and be triggered when the victim performs a common action. Examples of this include loosening the bolts in a chair so that it collapses when sat upon, or placing a bucket of water on top of a partly open door so that when the door is fully opened, the bucket tips onto the victim. A variant is the water bucket which when "thrown" at the target, is full of confetti. See also Area denial Anti-personnel Anti-handling device Cartridge trap Combat engineer DEMIRA Deutsche Minenräumer Improvised explosive device Mercury switch Microswitch Mantrap Spring-gun Booby prize Protocol on Mines, Booby-Traps and Other Devices References External links US Army Training Film from 1944 (humorous cartoon with a serious message) Mines & Boobytrap devices - British guide dated 1943 How not to get caught by mines and boobytraps - US warning guide dated 1944, and still relevant How not to get caught by Vietnamese boobytraps - US guide dated 1969 Army Field Manual FM531 Boobytraps - US guide dated 1965 Photos of booby trap devices used in Angola Booby trap concepts and detection techniques The Straight Dope: What's the origin of "booby trap"? Photos of injuries inflicted by explosive boobytraps (Warning: graphic images)