Instable magic flow

Your supply of magical energy has become erratic, and changes drastically in short amounts of time. 

When casting a spell roll 1d4.

On a 4, Upcast your spell by one level, cantrips double their damaging dice 

O a 3 or 2, Your spell is cast with no additional effect 

On a 1, Downcast your spell by one level, cantrips automatically fail 

You may reroll this d4 equal to 1+ your spellcasting modifier per long rest.