STINGY WITCH - $5
ACTION - ATTACK
+1 Card
+1 Action
Each other player discards a card from hand, draws until they have 4 cards in hand, then either gains three Coppers, putting one of them in hand, or gains a Curse to their hand, their choice. (They may pick an option they can't do.)
I redid my card, and changed it quite a bit. While the basic premise of choosing what kind of junk your receive (Copper or Curse, with a penalty for choosing Copper), the mechanics are almost completely different.
At it's most basic function, this version replaces one card in each opponent's hand with a piece of junk. But from there it gets...different. The opponent chooses if they receive a Curse or a Copper; if they take the less harmful Copper, they get a lot more of it. At this level it's extremely powerful--it's both a hand attack (although they usually end up with the same number of cards total) and a potent junker. As a cantrip, you can potential fill your deck with them and play them multiple times a turn. That would seem overpowering.
But the attack's limitation's are real as well. The discard-first mechanic prevents multiple firings from ruining a turn, as the player can continue to discard the junk previously received. And after the Curses run outs, it turns into a relatively weak handcard attack, but still with the option for Copper (unless that runs out as well).
What's different about this, and why I think it works as a cantrip, is that (imo) it has the highest risk of any attack of backfiring, and actually helping the victim. If any of the cards in the other player's hand are dead cards, they can increase their buying power, potential to an important threshold. Indeed, playing Stingy Witch against an opponent with a hand of Gold-Silver-Silver-Province-Curse could cost you the game. (Something like that could happen with Margrave if an opponent had Gold-Gold-Copper-Province-Province and drew a Silver, but that would rely on something in the opponent's deck).
This only becomes more likely as your opponent gains more Curses and/or starts buying Victory cards. It also becomes more likely if you have a lot of these and keep using them after the Curses run out, as each one after the first sifts your opponent's hand, giving them the option of adding the (potential last-needed) Copper to each new incarnation of that hand. Unless they can be trashed, you're left with the choice of giving your opponent that opportunity or leaving them dead in your hand. And of course, if the Kingdom has good trashing, the junk is less of a problem.
That said, it's definitely a potent Attack. Because of that, and because it continues to work as an attack (albeit with increasing risk) for the entire game, I took away the +Buy. You don't need it.