Cold gun

The Cold Gun is a weapon that was designed by Cisco Ramon at S.T.A.R. Labs, to stop Barry Allen in case he used his powers with malicious intent. The gun was snatched by Basil Nurblin, and later taken by Leonard Snart, who used it in his guise as Captain Cold. The weapon would change multiple owners, ending up in the hands of Ray Palmer, self-titled Colonel Cold. A 2014 version of the gun was used by Snart while he was a member of the Legion of Doom.

History
The gun was designed by Cisco, unknown to both Harrison Wells and Caitlin Snow as a failsafe in case Barry ever turned out to be dangerous or was unable to control his powers after he woke up from his coma.

Basil Nurblin, posing as a S.T.A.R. Labs janitor, stole the gun and brought it to Leonard Snart as a means to defeat the Flash. After killing Nurblin with the gun, Snart continued to use the weapon as his weapon of choice, deciding to attack the Central City museum, managing to not only shoot Barry in the stomach but also kill a security guard. Later, the gun was used to derail a train as Snart was about to make his get away from the robbery of a diamond, only to be stopped from killing the Flash by Cisco, Caitlin and Felicity Smoak who claimed to have a cold gun that was more powerful than Snart's, he later departed and kept the gun with him, turning off the GPS system that was built into it.

Snart used it in his partnership with Rory, first firing it at the Central City Police who had anti-cold shielding in the form of compressed heating ribbons in their ballistic shields, then against the Flash himself. Ultimately, it was disabled by "crossing streams" with the Heat Gun, with their respective "absolute cold" and "absolute hot" cancelling each other out and disabling both weapons, with them both being taken into the custody of Cisco Ramon at S.T.A.R. Labs.

After Cisco was captured by the Rogues, they forced him to make a new Cold Gun for Leonard, to replace the one that was taken from him, otherwise they would kill Cisco's brother Dante.

When Lisa Snart came to Team Flash for help, thinking that Leonard Snart was kidnapped, Cisco demonstrated that the Cold Gun could be traced through military technology and be located from where it was last used. When Leonard Snart was forced to work with his father, Lewis, he used the gun to freeze the beams of the laser gird, effectively dispatching it.

Snart later upgraded his Cold Gun following his breakout from Iron Heights; he made it so that if he lets go of the handle of the gun at any stage, the core of the gun goes critical and it will explode.

After Snart's death, Mick Rory kept the Cold Gun, and attempted to teach his new partner, Carmine Broome, to use it. However, he ended up killing the partner in exasperation.

In the aftermath of the Legends' mission in 1863, Mick gave the Cold Gun to Ray Palmer, who temporarily used after his A.T.O.M. Exosuit was destroyed. At first, Ray thought that he could make some improvements on the gun though Mick told him that the gun was fine the way it was. Ray used it during the Legends' mission in 1987 when he, Mick and Sara were swarmed by the Secret Service. He and Mick used the weapons to try and keep them at bay but Ray accidentally moved and crossed the Cold Gun's stream with the Heat Gun, causing an explosion that knocked both Mick and Ray off their feet. He then used components from the gun to disarm a bomb that Damien Darhk placed inside the White House. Ray stopped using the gun after he found more dwarf star alloy in the old West, some of which he used to build a new A.T.O.M. suit.

When Barry Allen went into the Speed Force to rescue Wally West, he ran into a version of Snart who used the Cold Gun against both him and Jay Garrick.

After the Legion of Doom recruited a past version of Snart into their team, Leonard used a 2014 version of the gun when working with the Legion. He used it in the Legion of Doom's alternate reality to try and kill Nate Heywood. Later the gun was vital in knocking out Eobard Thawne. However this only stopped him for a short time. After taking down Eobard, Leonard used the gun to kill Amaya Jiwe by freezing her into a block of ice, proceeding to shatter her into pieces. When the Legends of the present and future fought the Legion, Snart used the Cold Gun to knock Ray Palmer out of the sky and then used it to shoot a shard of ice into the future Mick's chest and kill him.

Caitlin used a Cold Gun when Barry went on a brief rampage in S.T.A.R Labs, due to his fugue state resulting from his time in the Speed Force. She also held the Cold Gun at the ready when Gypsy unexpectedly opened a breach in S.T.A.R. Labs, headed to Earth One for a date with Cisco. It's unknown if this is the same Cold Gun that Cisco had built four years previously (which had been stolen from S.T.A.R. Labs, but was later reclaimed from Leonard Snart), or if Cisco had built another one.

Weapon specifications

 * Absolute zero blast: The gun, as explained by the thieving S.T.A.R. Labs janitor who stole it, shoots a blueish "white flame" that lowers temperature. In actual fact, the gun contains a micro-engine that generates a blast or beam of absolute zero or subzero cold. The engine projects the cold as a blast that can freeze anything on impact. It's so powerful, it incapacitated The Flash and slowed his speed. The goggles that came along with it are a way to protect the user from the glare of said blast.
 * GPS system: The gun has a GPS system built into it, it can be tracked by S.T.A.R. Labs, however, the GPS can also be deactivated by the user. The second version of the gun, lacking this system, relies upon the tracker to search for ultraviolet "cold" signatures through military tracking technologies.
 * Self-destruction: At some point, Snart modified his second Cold Gun so that if he releases his grip from the handle, the core would go critical and explode.

Weapon drawbacks

 * Limited power supply: The Cold Gun has a limited charge capacity and thus has to be periodically re-charged each time it runs out.
 * Heat Gun: If the Cold Gun crosses beams with that of the Heat Gun, both weapons will temporarily be disabled.

Known users

 * Leonard Snart/Captain Cold (formerly)
 * Carmine Broome (temporarily)
 * Ray Palmer/Colonel Cold (formerly)
 * Caitlin Snow

The Flash
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DC's Legends of Tomorrow
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Trivia

 * Snart had memorized the entire design of the Cold Gun, that way he could repair it if it was damaged. He had Rory do the same with his flamethrower.