Cryolator

The Cryolator is a unique weapon in Fallout 4.

Background
A part of the Vault 111 experiment, besides using cryosleep pods, was to find other uses for cryotechnology, primarily using it as a weapon. Conceptually, it is a flamer that shoots ice.

Characteristics
The weapon creates a cryogenic spray when fired that fades away at mid-range. Firing continuously at an enemy may freeze it solid and render it unable to move or attack for a period of time. More durable enemies will require longer exposure, and some cannot be frozen at all. The Cryolator can chew up large amounts of (rather expensive) ammunition, so use it wisely.

The crystallizing barrel mod will convert the weapon into an automatic crystal shooter. This makes the weapon far more ammo-efficient, as well as granting additional benefits such as increased range, increased damage (crystals do ballistic as well as energy damage), and a very small AOE. However, the projectiles do not travel particularly quickly and suffer from a noticeable flight trajectory.

Locations
Inside Vault 111, in a display case in the Overseer's Room behind a Master level lock. It cannot be picked up at the beginning of the game due to the inability to pick Master level locks before exiting the Vault. Interaction with the case prompts a line from the Sole Survivor, saying that they will return for it later. An entry on the Overseer's Terminal in the same room can be found detailing the weapon and why it was built.

Bugs

 * If taking Dogmeat to Vault 111 and ask him to find useful items near the Cryolator, he will take it out for the Sole Survivor to use. The player character does not have to reach the required level. (If ammo cannot be found, check Dogmeat's inventory.) . This bug is no longer present as of patch 1.3.45. (Tested March 12, 2016 - This Bug does work on PC, or has recently been re-enabled.)
 * After a cleared area resets, enemies killed with the Cryolator may respawn lying on the ground, completely unable to move or attack. These enemies will be in this immobile state every time they respawn.

Gallery
Cryolator Криолятор