What is your vote for the most overpowered spell in the game?

[KongMysen]

I'm going for stoneskin and phantom. Remove these 2 spells and a lot of tactics would be obliterated.

In my last game I used the Black Knights for the Final part of the game. Resistance went from 52 to 92%, and it boosted defence by 40% which at that time meant around 30 points to defence when mastery was on max.
That means a whopping 92% damage reduction from most physical enemies. An attack on a Black knight with 52% resistance which normally does 1000 dmg will only do 80 dmg on a black knight with Stoneskin on. The two hardest bosses in the game becomes very very easy even without evlin.

Baal is easy on impossible mode = overpowered spell. (and unit)

Phantom should be nerfed for the next game, so that unit skills won't be allowed for the summoned unit. It would still be a good spell for the extra tank and dmg output. OR the mana cost should be greatly increased.
Summoning paladins, green and bone dragons, inqusitors, dryads, demonologists etc for their skills makes it overpowered imo.