Glaring Armor (Patreon)

Armor (any armor), uncommon

This armor has a stylized face on the front, which occasionally blinks while it's worn. While wearing it, you can use a bonus action to speak its command word to cause the eyes to widen and stare directly at another creature of your choice that you can see within 30 feet of you. The armor continues to stare at the creature for 1 minute or until you are incapacitated, are no longer wearing the armor, or are more than 30 feet away from the chosen creature. For the duration, that creature must succeed on a DC 13 Wisdom saving throw whenever it attacks a creature other than you for the first time on a turn, provided it can see you. On a failed save, the creature takes a −1d4 penalty to its attack rolls until the end of the turn, including against the triggering attack. Once this property of the armor has been used, it can't be used again until the next dawn.

It's rude to stare.