It reduces the cost of your instants and sorceries by an increased amount for each oil counter on it
I had been searching the internet for info on these banned cards
played: 2.552.548087635 9% of decksPercentage of decks that could play both Smashback Alehorn and Mighty Windup (Yellow) that play both
Then again, this would also be subject to different interpretations of Un-sets, as stated in the beginning, so your mileage may vary.
Veronica, Dissident Scribe I might have the order on one and two backwards here, given that three-drops have steeper competition for Cube inclusion than twos, but Veronica, Dissident Scribe is easily the more exciting of the two cards
The weakest cards in this deck is probably Goblin Electromancer who doesn't reduce that many spells in cost and tends not to deal much damage either