Persistent Nightmare is really underwhelming, though. Sure, it has Skulk, meaning that any creature with more power than it can’t block it. If it gets to deal combat damage to a player, it returns to your hand. So cool, you get to cast Startled Awake all over again! Sure, but how good is that really? Mill is an extremely popular archetype among casual players, and heck, it occasionally wins a tournament or two. It’s pretty fun with Sphinx’s Tutelage from Magic Origins, even without ever using its flipside. It’s like Persistent Nightmare exists for the sole purpose of being annoying. It could be potentially useful, too, but that’s quite an investment - 4 to initially cast, 5 to reanimate, and then having to deal damage? You could also discard this card, or mill this card, at some point, bring it back for 5, deal the damage, then get it back to your hand.
Like many cards in Shadows Over Innistrad, this card is extremely well-designed from a flavor perspective, but is rather conservatively costed. Really, this is a mythic so that it doesn’t break Limited. At rare, this would be an auto-include in any blue deck, as milling 13 cards out of a 40-card Limited deck really hurts an opponent. Being able to come back in anyway is pretty devastating in that case. Cast this on turn 4, bring it back on turn 5, swing with it on turn 6, get it back and recast it for probably the rest of your opponent’s deck. That’s why it’s a mythic. That way, it doesn’t show up in every draft deck ever.
This seems like a big time casual hit to me. Heck, I’d probably play it in a Circu, Dimir Lobomist, Mirko Vosk, or Phenax, God of Deception EDH deck for funsies. It’s not a card that should see much competitive play outside of big time Limited tournaments - where it will be good. The fact that it can keep coming back seems to make it EDH playable. Some opinions so far seem to think it’s not even good there, but Commander is a format where people play what they want and I would play this. So I’m on this card’s side. As I said, it’s a way to speed up all of those Sphinx’s Tutelage decks people like to play. I’m not sure how good that card is without Khans of Tarkir and Fate Reforged around, losing Treasure Cruise, and Outpost Siege or Monastery Siege. Chandra, Flamecaller is around, though, and people are brewing with her in Tutelage decks. So Startled Awake could sneak into a deck like that.
Startled Awake is a big flavor win, and while I wouldn’t ever buy a copy at pre-order prices, it’s one I’d play in Commander in the right deck, for sure.