Mr. Freeze, real name Victor Freeze, is a criminal working for Intergang appearing in the Smallville Season 11 comic story arc "Detective".
Victor Fries was once a scientist in the field of Cryogenics and hoped to preserve his wife Nora in a cryogenic chamber of his own design until a cure could be found for her illness. An accident occurred in the lab making Victor Fries exposed to his own cryogenic formula which made him become Mr. Freeze.
Mr. Freeze became an agent for Intergang so he could obtain money to continue researching a way to save Nora.
At a safe house, Joe Chill was confronted by Batman who attacked him for murdering his parents until Superman calmed him down. Superman calmly explained to Joe Chill that they needed to locate a man known as the Trickster whom they believed was developing the weapons Chill would sell to the Intergang.
Mr. Freeze and the Prankster arrived to kill Chill. While Superman tried to distract the villains, Batman was trying to get Chill out of the area. Mr. Freeze killed Chill and framed Batman for the crime and Batman escaped with an injured Superman while the FBI were in pursuit of them.
Batman and Superman arrived at a location to confront Prankster who attacked him with a robotic suit that Toyman developed.
Prankster revealed that Mr. Freeze was brainwashed by him and attacking the citizens of Metropolis and is suit's fuel cells are overloading and will explode and with Freeze above Metropolis' water purification plant, anyone within one mile will get killed in the explosion.
Superman went to stop the Prankster while Batman was able to take down Mr. Freeze with help from Green Arrow.
Mr. Freeze was sent to Arkham Asylum where he became a member of the Yellow Lanterns as well as Bane and Poison Ivy all because of Parallax. Fortunately, Professor Hamilton found a way to reboot the rings so that all the Yellow Lanterns would loose their powers when the rings turned black.
Once Hamilton did that, the inmates of Arkham Asylum nearly fell to their deaths from the sky until Superman was able to save them all. After Parallax was defeated, Freeze and the criminals were returned to Arkham Asylum.