Crone of Cold

You extend a finger and point at an open area 5 ft square that you can see within range. summoning a ghostly blue illusion of an old lady who laughs knowingly before disappearing in a burst of ice shards. the resulting Ice turns the ground in the area into difficult terrain until the start of your next turn.

Each creature within 15 feet must make a Dexterity saving throw. It takes 1d6 Cold damage and be knocked prone on a failed save, or take half as much damage on a successful one. 

When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1st.