Also, my examples of Cellar or Oasis were incorrect. When cards discard other cards from your hand, you would just choose to discard Retriever.
The good news is that there are still plenty of cards that discard during your turn from the top of the deck, for example, Hunting Party, and other cards where you "discard the rest".
This card makes me think of rule questions... like when you discard multiple cards from your hand (Cellar/Warehouse-style), do you do that one at a time or all at once? If the latter, I am unclear on whether you could react to a multiple discard with 2 Retrievers to get 2 cards or if in that case lose-track would apply for the cards that aren't on top of your discard pile.
It's all at once; this has always mattered in terms of giving your opponent info; they only get to see the card you choose to put on top of your discard.
So yes, Lose Track should apply. It seems similar to Tunnel, which already requires you to reveal a card that is lost tack of if you discard multiple Tunnels, but Tunnel's reaction doesn't require you to actually move it; only to reveal it.
Very good points! Seems like two potential issues:
1. Retriever gets discarded on top of the discards and you would lose track of anything below.
2. Discards for cards like Cellar are all at once.
The first can definitely be solved by another rewording: if you first set Retriever aside and discard at a later point (Clean-up, for example), then it won't immediately cover anything up.
Would this also handle the 2nd case, since you would have moved the top card from the discard into your hand?
In other words:
You Discard two cards, A and B, putting A on top B on top of discard pile.
Set aside 1st Retriever, move A to your hand (revealing B now on top of discard pile).
Set aside 2nd Retriever, move B to your hand.
Is that correct? Or are you not able to "recover" track of B after it gets covered up? I'm pretty sure I've read some similar examples somewhere, so I'll look and see if I can find any precedent.