Unstable wild magic

Your magic only goes wild if you roll a 1 on your dice of whether or not your magic goes wild. 

The first spell you cast, you roll a d10 to see if it goes wild. 

If it doesn't, next spell you roll a d8.

After that would be a d6.

Then a d4

Then flip a coin (you decide what side makes it go wild) [if you don't have a coin, use a d4 and make 1 and 2 both go wild] 

Then it just goes wild. 

Every time it goes wild, it then bumps back into a d10 on whether or not it goes wild next time. 

The dice you're on is maintained throughout rests.