Wrath of the Kaiju, pg. 182
You have trained in the dense, rolling fog along the dangerous Umigiri Coast. You gain the following benefits:
• Increase your Strength, Dexterity, or Constitution score by 1, to a maximum of 20.
• When you hit a creature with a melee weapon attack, you can cause the weapon to exude a dense fog in a 10-foot radius. If you hit with an unarmed strike, the fog exudes from your breath. The area of the fog is heavily obscured for all creatures other than you until the start of your next turn. You can use this benefit a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.