Salty (5e Feat)
From D&D Wiki
Prerequisites: Charisma 13 or higher
You can't survive my fireball spell! Th-that's illegal!
Sometimes people do better than you or best you in some way and you just get really mad. But you channel it in an impressive, passive-aggressive way that soothes your own ego.
You learn the vicious mockery cantrip. Charisma is your spellcasting ability for this cantrip. When you have cast a spell that deals damage or attack, and there is still at least one targeted creature that is not unconscious, you may use your reaction to cast vicious mockery against that creature. You can do this a number of times equal to your proficiency bonus, you gain back all uses on a short or long rest.