Homebrew
0-level (Cantrip) Enchantment
You flourish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the attack's normal effects, and becomes provoked by you. Until the end of your next turn, if the target makes an attack roll against a creature other than you, it takes 1d8 psychic damage and the spell then ends.
At 5th-level, your attack deals an extra 1d8 psychic damage to the target, and the damage the target takes for attacking someone other than you increases to 2d8. Both damage rolls increase by 1d8 at 11th-level (2d8 and 3d8) and 17th-level (3d8 and 4d8).