Cold gun

A cold gun is a weapon that can generate and project air at sub-zero temperatures. The more effective versions of a cold gun actually produce ice, which is a helluva lot cooler than a gun that is little more than a hand held air conditioner.

A cold gun is the trademark weapon of a DC Comics superhero named Captain Cold. Captain Cold is a foe of the Flash and a member of a supervillain team called the Rogues Gallery. Captain Cold's cold gun can produce and fire ice of various volumes and intensity. This includes firing sharp icicle darts, forming simple geometric shapes like a wall or a bridge, or creating large thick barriers of ice, which he can use to shield himself from oncoming attacks.

DC Animated Universe
Captain Cold used his Cold gun to ambush the Flash at the Flash Appreciation Day ceremony at the Flash Museum. During this affair, he primarily used it against Flash's colleague in the Justice League, Orion. He froze Orion in place with an ice sheathe, but Orion broke free of it. He then froze the legs of Flash's other teammate, Batman. He turned the gun on Orion a second time, but Orion countered with a pressurized water main, which froze upon making contact with the cold gun, turning its effect back upon Captain Cold, freezing him in place.

DC Television Universe
Leonard Snart from The Flash appropriated a cold gun from S.T.A.R. Labs, which had actually been designed by young scientist Cisco Ramone. Along with his partner Mick Rory, aka Heat Wave, Captain Cold used the cold gun to commit crimes and to battle up against the Central City Police Department. He fought up against the Flash and ultimately learned his secret identity. A reluctant truce was formed between the two, which enabled Snart to keep his cold gun.