Suggestions for giving kassadin a silence

Q: if the projectile hits an enemy while they are using an ability they are silenced

W: if kassadin hits an enemy from behind they are silenced

W: gains stacks when kassadin hits an enemy champ, at fourth stack the next enemy hit is silenced

E: can now gain up to twelve charges, at six charges the ability is the exact same as it is currently, at twelve charges enemies hit are silenced

R: at fourth stack enemies hit are silenced