Cryogen was a gas used in the field of medicine during the final days of the Galactic Republic. Typically inert until it was mixed with oxygen, Cryogen was used to freeze cells and tissue samples for later use, this substance became important during the Clone Wars when clone trooper's various transportable cloned organs could be shipped and stored in cryogen and transported across the galaxy.
The substance also had offensive purposes, being used with whips by Bartokk assassins. When the weapons struck, they caused cold, near-explosive, chemical reactions capable of freezing metal in a single strike.
- Maul: Lockdown
- Episode I Adventures Game Book 4: Jedi Emergency (First appearance)
- Medstar II: Jedi Healer