Somewhere in the Secret Histories Donald mentioned that he had more ideas for one-shot cards, and that we might see more in the future. I think one-shot cards are very interesting strategically, but it's hard to see how games would work if many or most of the kingdom cards were one-shots. This put in my head the idea of a card that would allow you to recover your one-shots. Rather than another "sift through the trash pile for goodies" card, I envisioned a reaction that would work like a reverse Watchtower -- allowing you to gain cards that had just been trashed.
In order to make the card relevant, though, it has to do something else as well, and it probably needs to ensure that cards get trashed. This could mean one of three things: make it a trash-for-benefit card, make it a trashing attack, or make it a one-shot itself. All are interesting possibilities.
Meanwhile, I've been thinking that there should be a card that allows you to put gained cards directly into your hand, which also is a spin-off of Watchtower. The common connection to Watchtower led me to combine the two ideas as follows:
In plain English the card can react to three different events: (1) if a card from your deck was just trashed, you may gain it (to your discard pile); (2) if you just gained a card, you may move it to your deck; and (3) if you just placed a card on your deck, you may place it in your hand. Obviously in order to keep a trashed one-shot from coming right back into your hand, this card would have to use a reveal-and-discard mechanic.
Notice that this reaction would not allow you to trash incoming curses, so in that respect Watchtower still has a unique function. But it would allow you to snatch back the Colony that just got Sabotaged (you also get to gain a Platinum, because your Colony was in fact trashed, but the Plat can't go on top of your deck if you intend to save your Colony).
If that's all the card does though, then it only serves as a half-watchtower in games without certain trashers or top-decking potential. But I'm already worried that there is no sufficiently concise way to word the reaction component. Also, this card could be terribly confusing with Possession, could make Forge, the Remodel family, and trash-for-benefit cards very powerful, and would completely nerf Saboteur.
As for the name, I'm inclined to go with Magician, as it connotes both bringing the "dead" back to life and sleight of hand with cards. I would welcome any thought on cost, whether an action is necessary and what it should be (I like the idea of a card that is simply a reaction, if it is worth buying), and any other potential problems I may have overlooked (I'm sure there are many).