This spear has an uncommonly large head with a blueish hue and an intricate etching of a winter landscape across it. When thrown it creates a billowing cloud of snowflakes in a 10 foot radius around where it strikes whether it hit its target or not. Any creatures within the radius are blinded until they leave the area or it dissipates. The cloud dissipates at the end of your next turn.
Once per short rest if you successfully hit a creature with the spear you can force that creature to make a Constitution saving throw equal to 12 + your proficiency modifer. On a failure they are restrained for 1 minute as ice freezes them in their tracks. They may repeat this saving throw at the end of each their turns.
Additionally, if driven into the ground as an action it freezes the ground and everything not held or worn within a 15-foot radius, which is treated as rough terrain until the spear is picked up again, and all non-magical fires within the radius are extinguished.