Quietly or not-so-quietly, Thought-Knot Seer is one of the most impactful cards from Oath of the Gatewatch. The ability to strip the opponent's best card while providing a fast clock is well worth four mana, even if one of it has to be colorless, and Thought-Knot shows up even in formats without Eye of Ugin.
What if I told you there was a bigger version of Thought-Knot Seer, one that doesn't stop at just taking one card? It might cost a little more mana, but there are ways around that, too, as its unsuspecting victims will soon find out.
Take a look at Distended Mindbender:
There's a lot going on here, so let's take it line by line.
First of all, it costs eight mana. That's tough, but it doesn't really cost eight, thanks to emerge.
An emerge cost of 5BB means that you can sacrifice a creature not only to make the cost start at 5BB, but to reduce it by whatever that creature cost. Note that the minimum you end up paying is BB, as emerge just looks at the converted mana cost of whatever got sacrificed. Still, casting an eight-drop for two mana is cause for celebration, and you don't even have to go that deep to play this on turn four.
The curve of turn three three-drop, turn four emerge out Distended Mindbender is soon to be a feared one, and if you are sacrificing something like Matter Reshaper, you are barely paying a cost. Speaking of costs, what do you get for all this?
To start with, a 5/5. Distended Mindbender is not a small creature, and 5/5 is big enough to be considered a respectable finisher in its own right. It beats most creatures in combat, and takes large enough chunks out of the opponent that it can close out games in just a few turns. The real payoff, though, is in its mind-bending ability.
Making the opponent discard a card that costs three or less and a card that costs four or more is not something we've seen before, but it's not hard to see that it's extremely powerful. First of all, you will always get at least one card unless your opponent is holding all lands. That's a fine baseline, and you will get two cards frequently. Any time your opponent has five or more cards in hand, you are a favorite to get two cards (depending on their deck, of course), and some decks give you a good shot even with just three or four cards in hand.
Add all this together and we get a potent threat. Distended Mindbender can come down on turn four or five, take two of the opponent's best cards, and stick around and demand an answer (which they are less likely to have after the ability resolves). It takes a little work, as you won't typically see this in decks without creatures to sacrifice, but we have a lot of good creatures to feed the Mindbender running around these days.
Later in the game, this might only hit one card—or even none—but at that point you are more likely to be able to just cast it. Sacrificing a creature isn't mandatory, and playing eight mana for this is not a disaster by any stretch.
All told, Distended Mindbender is quite the card. It takes some deck building in order to truly harness its power, but the payoff is well worth it. I expect to see plenty of other cards with emerge, which means you have other incentives to build your deck in such a manner, and having this as your high-end threat is a very good plan. I wouldn't count on seeing the last of Distended Mindbender anytime soon.