Unlucky Streak

Choose a creature within range that you can see. The target must then succeed an Intelligence saving throw or become cursed with bad luck for the duration of the spell. Until the spell ends, the target must use a d12 instead of a d20 for all attack rolls and ability checks. Rolling a 1 when under the effects of this spell does not count as a critical miss. At the end of each of the target's turns, they may repeat the Intelligence saving throw, ending the spell on a success. 

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the target must instead use a d10 instead of a d20. The die then becomes a d8 if the spell is cast at 8th level or higher.