Davy Crockett (nuclear device)

The M-388 Davy Crockett was a tactical nuclear recoilless rifle projectile that was deployed by the United States during the Cold War. One of the smallest nuclear weapons ever built, the Davy Crockett was developed in the late 1950s for use against Soviet troops had war broken out in Europe. Small teams of the Atomic Battle Group (charged with operating the device) would be stationed every few kilometers to guard against Soviet attack, using the power of their nuclear artillery to kill or incapacitate advancing troop formations and irradiate the area so that it was uninhabitable for up to 48 hours, long enough to mobilize NATO forces.

From: http://en.wikipedia.org/wiki/The_Davy_Crockett