You read that correctly. If you're up against Loatheb in Heroic Mode, the Plague Quarter Boss will not tolerate any easy ways of winning the game. The first wing, Arachnid Quarter, allowed you to play Alexstrasza to bring down your opponent's lifepoints from 45 to 15. This time, however, Loatheb will say "This is Heroic... No cheap tricks allowed!" and then follows it up with the demise of Alexstraza. Additionally, you won't get your used mana back, aside from the effect being cancelled.
Good luck!
