Hoarfrost of Stygia

You learn to call upon devilish ice to harry your foes. You gain the following benefits:

• Increase your Dexterity, Constitution, or Charisma score by 1, to a maximum of 20.
• When you roll cold damage for a spell you cast, you can reroll any roll of 1 on the cold damage dice, but you must use the new roll, even if it is another 1.
• Whenever you cast a spell that deals cold damage, you can cause icicles to form around you until the end of your next turn. The icicles cause the ground within 10 feet of you to become difficult terrain, and they don’t hamper you or your allies. While the icicles are present, any creature within 5 feet of you that hits you with a melee attack takes 1d4 cold damage.