Freeze Gun

The Freeze Gun is the custom made weapon of choice used by Mr. Freeze.

Batman Issue 121 & Batman (1960s series)
The freeze gun first appeared in Batman Issue 121 back in 1959 when Mr. Freeze was known by the name of "Mr. Zero" and used his knowledge of cryogenics to procure wealth. This remained unchanged by the 1960s TV Series.

Batman: The Animated Series
By 1992, Mr. Freeze's character was re-imagined to be more sympathetic and one of pure vengeance. In the emmy award winning episode Heart of Ice, Freeze constructed his freeze ray sometime after constructing his cryo-suit, which he would use to steal parts from his former place of work Gothcorp. These parts were needed to construct a large freeze ray needed to battle his former company of employment. After being taken into custody by Batman, Freeze's suit and weapon was confiscated.

Cold Cold Heart
In the DLC pack of Batman: Arkham Origins, Freeze utilized an advanced suit with two powerful freeze rays built into the arm. He used this to invade Wayne Manor in search of Ferris Boyle whom he managed to find and brought him to Gothcorp. Once there, Freeze demanded Boyle that he give him the codes needed to access the lab his wife Nora was being held, even going as far as threatening to freeze Boyle so he would share his wife's fate.

When Batman arrived, Freeze and his men began combating the caped crusader. He was defeated by Batman and almost killed by Ferris had it not been for the Dark Knight. After this, Freeze's suit and weapon was confiscated after being sent to Arkham Asylum

Batman: Arkham City
When Hugo Strange had opened Arkham City, Freeze was one of the inmates sent there. He settled into the former GCPD building where he would continue his research in the forensic labs of the station. Freeze was captured by Pengiun, who took his suit and weapons due to the violent gang war he was in with The Joker and Freeze was working on a cure for the clown prince of crime.

While Freeze's suit was placed in an exhibit of the Iceberg Lounge, Penguin took possession of his freeze gun and used it against Batman, however Freeze gave Batman a method of disabling the weapon in the form of the Disruptor. This gave him enough time to disarm Cobblepot and take him down only for him to also have to take on Solomon Grundy as well. After the fight, Freeze reacquired the gun and returned to the GCPD building where he worked on a formula for the cure to the Titan strain killing both Joker and now Batman.

Batman returned, having engaged Ra's al Ghul in combat, gave Freeze the blood sample needed to make the cure. Having fabricated the cure, Freeze turned on Batman in hopes of demanding that he save his wife from the clutches of Joker. Angered by Batman's refusal, Freeze began a fight between himself and the caped crusader and used his freeze ray in the process.