Rastakhan's Rumble Guide
Battlecry: Remove all your minions. Deathrattle: Resummon them.
Has anyone tried to discard it using Howlfiend and Treachery when fighting against the Lich King?
No, I believe he draws it righ on turn seven.
probably a boss encounter in the new set
The Lich King or Arfus its one of the Death Knight "class" cards (not to be confused with Deathknight Heros), kind of like how Ysera had her own Emerald Dream cards