Chebald's Mind Goblins

You say the term "Mind Goblins" to someone in range where they make a Wisdom saving throw against your spell save DC. On a success, they do not inquire what a "Mind Goblin" is, on a fail, they are met with the phrase "Mind Goblin these nuts". The target takes 10d10 psychic damage, knocked prone and is frightened of you until they make a successful wisdom check against your spell save DC at the end of their next turn.