The concept here is very simple - the 'Mutiny' (or perhaps even 'Turncoat') spell is cast on enemy CC troops causing them to turn on their masters and begin attacking their own defences.
There are two key variables involved here to ensure the spell is balanced and not over-powered, one being the duration of time the spell lasts and the other subjecting the afflicted enemy troops with a damage differential i.e. 1/2 damage. These values could improve (in favour of the attacker) with increased levels.
Thoughts on a postcard...

