Flashfreeze Powder

You can blow a dose of this powder towards a creature within 5 feet with the Use an Object action. When you do, that creature must succeed on a Dexterity saving throw or take cold damage and have its movement speed reduced to 0 until the start of your next turn. This cold damage is equal to your Sneak Attack damage. If the creature succeeds on the saving throw, it takes half damage and its speed is unaffected.