Freeze Blast

The Freeze Blast is a high-powered sub-zero temperature projectile that is created by Mr. Freeze, which detonated on impact, and could be used to solidify water or temporarily incapacitate thugs.

Optionally, Batman could also acquire the Freeze Cluster Grenade in the Boiler Room at the Steel Mill, which operated the same way as the Freeze Blast, but had the ability to incapacitate multiple enemies.

Gameplay
The player had an unlimited supply of Freeze Blasts, which could be equipped by holding L1/LT/RMB (PS3/XBOX360/PC) and thrown by pressing R1/RT/LMB (PS3/XBOX360/PC). You could also initiate a "Quickfire Freeze Blast" throw by just tapping R2/RT (PS3/XBOX360 ) and it hits the closest or most important target without fail, unless you're aiming at a ninja or Combat Expert who can dodge it. Even though you have unlimited Freeze Blasts, only one can be active at a time, unless with an upgrade. If you throw one on a watery surface and try to throw another while you're standing on the raft made of it, Batman will say that a second Freeze Blast will destabilize the raft. Otherwise, throwing a second Freeze Blast will make the first one disappear. Additionally, if you Redirect by jumping over a enemy frozen by a Freeze Blast, it will also disappear.

The Freeze Cluster Grenade generally worked the same way as the Freeze Blast, but contrary to the latter, the player couldn't initiate a "Quickfire Freeze Cluster Grenade".

In both Arkham City and Arkham Knight, when used with an upgrade, namely "Freeflow Focus Power Gadget" and "Special Combo Freeze Blast" respectively, it gained an area of effect, and froze multiple enemies as long as they were standing close to the target.

Cold, Cold Heart Incident
A prototype of the Freeze Blast could be seen in Victor Fries' Lab on his desk at GothCorp.

Before Arkham City Incident
A little while before the events of Arkham City, Freeze was finally able to finish building the Freeze Blasts, but he wasn't able to test them because he was kidnapped by the Penguin to prevent him from finishing the Joker's cure for the Titan Disease.

Arkham City Incident
Batman received the Freeze Blast from Freeze, after the fight with him at the old GCPD Building, to help him defeat the Joker at the Steel Mill, and to stop Hugo Strange's Protocol 10.

While at the Steel Mill, Batman confronted a tied-up and gagged Harley Quinn, who inadvertently let slip that Joker stole something from Freeze and locked it in the Boiler Room. Batman traveled there and found the Freeze Cluster Grenade, which was guarded by Joker's Henchmen.

Arkham Knight Incident
The Freeze Blast was lying on a small table inside of Panessa Studios, next to the Quarantine Cells. It could be picked up right after Batman escaped from Ace Chemicals, when the player could freely visit the hideout.

Trivia

 * There's a glitch at the Steel Mill. After you beat the game, the Abramovici Twins would be reunited. If you threw the Freeze Blast or the Freeze Grenade on one of them, they would be paralyzed by the ice and you could beat them up.
 * There were a couple of Freeze Blasts sitting on Freeze's workbench in his lab at GothCorp in Cold, Cold Heart. On the floor next to the Freeze Blasts, there was a blueprint for them.
 * The Glue Grenade functioned exactly the same as the Freeze Blast.
 * It's not explained that what happened to the gadget after The Knightfall Protocol, as none of the (former) Robins had it on their Arkham Episodes. Even though Azrael could use it, he already had a replica in his Gotham's Most Wanted Side Mission, Heir to the Cowl. It's possible that the gadget was added to the GCPD Evidence Room.
 * There's a glitch in Arkham City. With this glitch, you can escape from Arkham City too. Find a building ledge or a billboard, then face toward the corner and start throwing Freeze Grenades (PS3: R2+R2 and X360: RT+RT). When you reach the edge, you will start to rise in the air. Continue spamming Freeze Grenades to gain altitude. Soon, you will rise above the smog of the city. When this happens, start gliding towards to Gotham City. You can't use the Grapnel Gun. You can't touch anything. This glitch doesn't break the Save Game.