If this demon deals combat damage to a player, you can nullify its damage and reduce their life total to 1
Later in the game, should the worst happen to the Pilot, you can pay four mana to bring it back to your hand from the graveyard
It hates on aggro and combo decks alike, slowing the game down to a snail's pace or whatever the equivalent of that is in blisteringly fast Vintage to let you cast monsters the nature of which are also dictated by format
Tamiyo, Inquisitive Student / Tamiyo, Seasoned Scholar seems like an option in Historic wizards that can get to its draw-third-card payoff, and someone will try brewing fevered combos with Sorin of House Markov / Sorin, Ravenous Neonate, but Im not seeing it
Basically, it milled the opponent every time he or she cast a spell