Source: Unearthed Arcana 85 - Wonders of the Multiverse

Prerequisite: 4th Level, Strike of the Giants (Frost Giant) Feat

You’ve manifested the icy might emblematic of frost giants, granting you the following benefits:

Ability Score Increase. Increase your Strength, Constitution, or Wisdom score by 1, to a maximum of 20.

Born of Ice. You have resistance to cold damage.

Frigid Retaliation. Immediately after a creature you can see within 30 feet of you hits you with an attack roll and deals damage, you can use your reaction to retaliate with a conjured blast of ice. The creature must make a Constitution saving throw (DC equals 8 + your proficiency bonus + the modifier of the ability increased by this feat). On a failed save, it takes 1d8 + your proficiency bonus cold damage, and its speed is halved until the end of its next turn. You can use this reaction a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.