One of the dangers of modified weapons: the firer sometimes takes the projectile when the firing device in this case a pengun, explodes. These penguns are far more streamlined than the firearm models and use compressed gas or electrical ignition to launch their deadly missiles. These are intended to kill, and that is why the CIA was 'experimenting with' and then was discovered hoarding a quantity of cobra venom and shellfish toxin in the mid-1960s. Improvised penguns are usually conversions of the tear gas and flare guns, e.g., the first British SOE penguns in World War II were tear gas guns to be used against potential captors or pursuing guard dogs. The simplest of these World War II devices was a two-part item consisting of a penlike body, which served as the barrel, and a cap, which was bolt and receiver with a fixed firing pin in its base. An agent simply slapped the base sharply with the flat of his hand, and the weapon fired. World War II was also the era of the large fountain pen.