Traso's deadly pats

You begin rapidly patting a creature on their head. That creature must succeed a Dexterity saving throw or take 1d8 + your spellcasting modifier bludgeoning damage and is stunned until the spell ends. At the start of the creature's turn while the spell is active, the creature may attempt the Dexterity saving throw again, suffering the same consequences as before on a failure and ending the spell on a success.

At higher levels: When you cast this spell at 2nd level or higher, the spell's damage increases by 1d8 for every level above 1st.