Time Knife

The blade of a dagger or shortsword you are holding is imbued with chronomancy. For the duration, you can use your spellcasting ability instead of Strength or Dexterity for the attack and damage rolls of melee attacks using that weapon, and the weapon's damage die becomes a d8. The weapon also becomes magical, if it isn't already. When you attack a creature and roll a critical hit using the imbued weapon, the target must make a Constitution saving throw, or be stunned until the start of your next turn. The spell ends if you cast it again or end your turn not holding the weapon.