Alternate names: Distracted Casting.
This would be a racial/personality based spell, not for everyone. Maybe Heretic since they would be into weird magic.
The spell upon successful cast will cast a RANDOM offensive spell on an enemy (duration or instant).
Seems kinda blah right.. well here's the twists.. The difficulty of the spell would be moderate (think fireball/greed) and You DON'T have to have access to the spell to cast it.
So for instance you are a heretic and your kd REALLY REALLY needs MS on an enemy mystic, well you can cast this and possibly have a chance at getting it on them.
The problem? Well besides the pure random nature of the spell, It would have weighted percentages leaning towards casting the easier spells (since it is an easier spell to cast). So like Storms would have a 10% chance of being cast and Meteor Showers might be a 4% chance or something. MV or LL might be 3%.
Anyway, not fully thought through, but it would surely add some randomness and fun to some wars, and make for some good situations and stories to bring up ages after it happens.