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Arrowverse Wiki

"Icicle" was the alternate personality of Thomas Snow.


Creation and containment

Around 1999,[1] Thomas Snow began suffering from amyotrophic lateral sclerosis (ALS). Thomas then experimented on himself using cryogenetic therapy and was able to eventually freeze the progression of the disease. In the process however, Thomas ended up creating Icicle, a malignant alter-ego.

Icicle became aware of Thomas' daughter Caitlin Snow's alter-ego, Killer Frost (known then as Khione), and fought Thomas for control, desiring to use his host and Killer Frost for nefarious purposes. With the help of his wife, Carla Tannhauser, Thomas sealed himself off in an abandoned Tannhauser Industries black-ops site in the North Pole to protect Caitlin and his loved ones from Icicle, faking his death in the process. However, Icicle refused to give up and arranged for Caitlin to receive messages from her "father", asking his daughter to come find him. Thomas had kept in touch with several scientists once going underground, including Dr. "Harrison Wells", who created a secret video feed from S.T.A.R. Labs to the site. Icicle and Thomas both used this to watch over Caitlin.[2]


About 19 years later in November 2018, Icicle was discovered in the black-ops site by Caitlin and her friends Cisco Ramon and Barry Allen.[3]

They learn that he was attempting to find a cure for his and Caitlin's ALS gene, which resulted in them both getting meta-gene. However, he claimed that unlike his daughter, who developed a split personality called "Killer Frost", he never developed one and is dying; with a serum based on Caitlin's D.N.A. being the only cure. Eventually, it is discovered that he did develop an alternate personality, dubbed "Icicle" by Cisco Ramon and Nora West-Allen, who was in control of Thomas's body the entire time and that he needed the serum to kill his other self. Icicle's plan is foiled when Killer Frost reemerges and destroys the serum, forcing him to launch himself into the air and escaped.[3]


Icicle battling Frost.

Icicle later returns intending to eliminate Caitlin and Carla's human sides. Just as Icicle is about to kill Caitlin, Thomas suddenly finds the strength to return to his human form. Then, Cicada appeared and knocked out Barry, so, Caitlin dismissed Thomas and Carla. They then went fighting, where Caitlin fell to the ground. As she recovered, Cicada threw the dagger at Caitlin, but Thomas jumped into the dagger's path, sacrificing himself for Caitlin, and died in her arms.[4]

Powers and abilities


  • Meta-human/Cryogenic physiology: After suffering from multiple sclerosis, Thomas began to use experimental cryogenic therapy to save himself, as he did to Caitlin sometime later. Due to this, he gained cryogenic-based powers and also developed a dual-personality (i.e. Icicle).[3]
    • Thermokinetic cryokinesis: Given the fact he used similar treatments on his daughter, it is likely that Icicle's powers work in a similar fashion to Frost's. He can thus create sheets of ice, or shoot spearlike icicles at opponents. Icicle can also create an ice slide and use her cryogenic powers to rapidly propel himself forward on the slide.[3]
      • Cryokinetic breath: Icicle can exhale cold mists to create mini ice crystals in his victim's lungs, which makes it difficult for them to breathe.[3]
      • Cold immunity: As a byproduct from his cryogenic powers, Icicle's cells can withstand subzero temperatures, as seen when he used a machine to lower the temperature of a room to absolute zero.[3]
      • Flight: By projecting his cryogenic powers beneath himself, Icicle can propel himself at high speeds through the air, creating a simulated version of flight.[4]


The Flash

Season 5


  • Icicle seemed uncaring that Killer Frost despised him, even when he planned on making her the only personality in Caitlin. Either he slipped so far into insanity that he didn't care, or his serum would eradicate all "warmth" in his "snow pack's" personalities.

Behind the scenes

  • In the main DC Comics continuity, Icicle is a legacy name associated with villains of the Mahkent dynasty.
    • Joar Mahkent a.k.a. Icicle was a Golden Age Green Lantern and a Justice Society villain. He was a European physicist that used an ice-based weapon that also allowed him to alter people's appearances. He wore a protective suit that kept him safe from the cold and made him look as if he was made of icicles. However, constant use of his weapon altered his genetics and gave him ice powers, which he passed down to his son before his demise during the Crisis on Infinite Earths.
    • Joar's son Cameron Mahkent, also known as Icicle, Jr. or just the second Icicle, went on to follow in his father's footsteps as a supervillain, sporting a more crystalline appearance as opposed to his father's icy look, and becoming a villain of the modern Justice Society. He went on to have kids with Artemis, and in a potential future, one of them took up the mantle of Icicle as well.
      • Cameron Mahkent was referenced on The Flash as a fake name used to cover the fact that Thomas Snow was alive.