So, the consensus seems to be in on Rats, and it's bad. Like, really bad - predictions are anywhere from bottom quarter $4 to the worst card since Scout. I'm here to defend it! (Please note that this is all speculation.)
Rats is obviously terrible in money. Like, so bad, really really bad. But that's not its purpose. Well, what is? Assuming good collision, Rats will clear your deck of starting Estates by your third shuffle. But, now you have four useless Rats instead of 3 Estates and a $4 card. Is that better? Not by itself, certainly.
Consider though that each time you trash a Rats, you get Labbed for free. Rats lets you choose to trash two AND draw two with Steward. Rats turns Junk Dealer into some kind of crazy Lab-Peddler-trasher hybrid monster. Quite possibly, the +1 card on trash is the biggest draw of Rats: if you could have otherwise built an engine by trashing your starting cards, you can gain +10 cards by doing so if you eat them with Rats first. (Note that this is however offset by the -10 cards you lose at the moment of trashing those cards; still, in many cases you would have trashed them voluntarily with no recompense.)
Perhaps more importantly, there are several cards which notably it will combo nicely with (Apprentice and Death Cart have been raised as examples), and I want to find more:
- Scrying Pool: Accelerates the removal of coppers/estates so you can reach deck-drawing faster
- Watchtower: On collision, turns Rats into trashing Labs
- Trader: Trade Rats for 4 silvers and 1 card
- Forge, Remake, Apprentice, Salvager, Remodel, Develop, Expand, Graverobber, Bishop, Governor: Adds $2-4 to cards which you would otherwise wish to be rid of, and also draws one additional card upon trashing
- Against Saboteur, Knights, Rogue, Swindler (to a lesser degree): Causes the risk of Labbing you and makes further Rogues useless
- Fortress: Makes Rats drastically safer to play to remove Coppers/Estates; with deck in hand, can pile Rats in one turn while trashing no other cards (ideally, to end the game)
- Poor House: Managing just two of these with no treasures in deck is a Province.
- Vineyards: In combination with some of the above.
All I'm sayin' is, don't discount it yet.
What are your thoughts on potential uses for this card?