Coercion! The more mindful Mind Rot!
This situation reminds me of what the Orzhov might do to children. The corrupt religious thang.
The first thing I do is check to see if there's at least another card in Visions at common or uncommon that does discard. And, yes, there are: Funeral Charm and Urborg Mindsucker! So, now I can do a different effect without neglecting black's "discard" piece of the color pie.
Next, I checked the mana curve of the black common cards. There's a good spread with the cap being a single card at four mana. There are four cards at two mana and four at three mana. Two cards at one mana. I think this card can be O.K. at the following mana costs: one, three, four, or five. If it remains at three mana, there's already another card that has two black mana in its mana cost, so it should be 2B. It's all right with double black at four or five mana, though.
Now I want to stare at the art and see if there's a top-down card waiting to happen. It looks like this guy could be teaching the young boy. Corrupt Teachings? That would fit alphabetically. Seems quite appropriate! Let's go with it.
Looks like teaching some corruption to a little boy is more of "affecting a creature" rather than the powerful planeswalker that is your opponent. I'd like to make this an Aura that does something bad for your opponent!
Before I go further, I need to see what kind of detrimental Auras there already are in Visions at common and uncommon.
- Death Watch hurts the opponent upon the enchanted creature dying.
- ...That's it.
O.K.! That's great! Because Corrupt Teachings is useless on a creature that is dead! We want the negative effects of the Corrupt Teachings to occur while the creature is alive. Perhaps the creature betrays its own master, revealing secrets! Or the creature would be a turncoat and hurt the opponent for you.
Ooh, this would call for a different name than Corrupt Teachings, if it revealed things like the hand for you. But then it would be a weird version of Telepathy. And revealing opponent's information to you is more of a blue thing, anyway.
Hmm. Let's take a look at all the monoblack creature Auras. It'll be informative, and surely not as necessary, but I'll get a kick out of it.
Whoa, dude. The new card Dying Wish from Gatecrash is almost like Death Watch. Subtly different!
Soul Bleed is kinda like what I want going on. Turns the creature into something that is working against its controller but not being hurt, destroyed, or doomed. Contaminated Bond, too.
Ooh, Treacherous Link is kinda along same lines of what I was thinking. Also, Binding Agony is slightly different but does the job all the same.
And done. All the black creature Auras. Fascinating.
If this creature is going to be taught to turn on its opponent, then it shouldn't fight for its opponent. That means we should stop it from fighting for his or her controller. It should do more than Contaminated Bond and not just hurt the opponent for having its creature attack or block - because Contaminated Bond-ed creatures can still hurt its controller's opponent's creatures.
I want this creature to be tapped, but I can't do that since that isn't a black thing. It's a white and blue thing. Instead, I need to not directly control what the creature can do. I need to make it so that it's punishing to the creature so that the opponent doesn't want to use the creature.
O.K., got it.
I costed it at three mana since that is the standard amount of mana needed to destroy a creature, and that's what this Aura is almost doing - rendering a creature useless. But since the creature can still block, it's not completely useless - which means instead of double black mana like Murder, it'll use just one black mana.
And I know the wording may be slightly too updated for Visions at the time, but that's nitpicking.