Multiattack

The hag attacks with its claws and uses Ice Bolt.

Claws

Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 4) slashing damage.

Ice Bolt

Ranged Spell Attack: +7 to hit, range 60 ft., one creature. Hit: 15 (2d10 + 4) cold damage and the target makes a DC 15 Constitution saving throw. A creature under the hags curse automatically fails this saving throw. On a failure the creature is restrained as it begins to turn to ice. At the end of the creatures next turn the creature repeats the saving throw. On a success the effect ends. On a failure the creature is petrified into ice. This petrification can be removed with greater restoration or similar magic.

Shapeshift

The hag magically polymorphs into a Small or Medium humanoid or back into its true form. Its statistics are the same in each form. Equipment it is carrying isnt transformed. It retains a streak of white hair in any form. It returns to its true form if it dies.

Invisibility (2nd-Level; V, S, Concentration)

The hag is invisible for 1 hour. The spell ends if the hag attacks or casts a spell.

Cone of Cold (5th-Level; V, S)

Frost blasts from the hag in a 60-foot cone. Each creature in the area makes a DC 15 Constitution saving throw taking 36 (8d8) cold damage on a failure or half damage on a success.

Wall of Ice (6th-level; V, S, Concentration)

The hag magically creates a wall of ice on a solid surface it can see within 120 feet. The wall is flat 1 foot thick and can be up to 50 feet long and 20 feet high. The wall lasts for 10 minutes. Each 10-foot section has AC 12 30 hit points vulnerability to fire damage and immunity to cold poison and psychic damage. Destroying a 10-foot section of wall leaves behind a sheet of frigid air in the space the section occupied. A creature moving through the sheet of frigid air for the first time on a turn makes a Constitution saving throw taking 17 (5d6) cold damage on a failed save or half damage on a success.

If the wall enters a creatures space when it appears, the creature is pushed to one side of the wall (hags choice)

The creature then makes a Dexterity saving throw taking 35 (10d6) cold damage on a failed save or half damage on a success.