Mistwell
Crusty Old Meatwad
And all it cost you was a boat load of party HP, maybe some of their actions, the battlefield being altered in a huge way, the fighter being a sheep now... the possibilities are endless -- like a spellcaster's spell selection endless.
It didn't cost you any of that. That was the enemies doing, not yours. Everyone in the party understands high level foes are dangerous. They're there for that fight after all.