- Remove cards from the game for the duration of the current scenario only. They're still part of your deck during this campaign.
Despite the heartbreaking imagery and flavor text, Abandoned and Alone is not that critical a weakness like some of the others are. Yes, taking two DIRECT horror could be game-ending, but knowing that this is in your deck, you basically make plans to ensure you have that two horror buffer (and with Wendy's starting Sanity of 7, this should not be TOO hard). Of course, sometimes you just have to take all that horror, which results in you being scared of being defeated by drawing Abandoned and Alone.
Abandoned and Alone removing all of your cards from your discard pile can range from inconsequential to devastating; the primary determination of which is whether or not you were planning to play Wendy's Amulet, or if you had something to pull out with Scavenging. Scenarios in Arkham Horror are generally so time-limited that you rarely draw through the entirety of your deck; making the reduced number of cards in your deck when you reshuffle a non-issue. As more investigator cards come out, we may see cards that interact with the discard pile, which may be an issue for Wendy decks.
There are not many solutions to the discard problem, but there are solutions to deal with the Horror aspect. Probably the best solution in the current Dunwich Legacy cardpool is to have Wendy put out her best ally buddy, Peter Sylvestre, to help deal with other sources of Horror (to ensure she has the buffer needed to take that direct damage). If Wendy has other allies she'd like to have (Leo De Luca and Cat Burglar to name a few) without investing in the additional ally slots that Charisma has to offer, then she could instead use a Smoking Pipe to help convert that excess horror away.
After this card is resolved, it's placed in the now empty discard pile. So if this is the last card in your deck, it removes the remaining discard pile from the game when you draw it and when you're required to draw a card again, it's the only card in your new deck. So you take 2 direct horror each turn, because it's the only card to draw each time.
A bad weakness or the worst weakness? Let's see. Looking at the two elements, the effect and the discard condition, we get:
The effect: Wendy Takes 2 direct horror and removes her discard pile from the game. The first effect is bad but manageable; Wendy has 7 base Sanity and has ways to heal horror and/or soak future horror. The second effect ranges from mild to devastating. Depending on when you draw the Weakness, it can remove most of your deck, killing recursion tricks, shutting down Wendy's Amulet, and possibly leaving you in a very short horror spiral to trauma for decking yourself and more horror for drawing this again. There are not many was to mitigate the effects, with Rabbit's Foot (3) being probably the best way to dig for it early, maybe abetted by Drawing Thin or Take Heart to increase your failure and draw more cards. Of course, if you don't hit it early, this tactic may exacerbate the damage when the Weakness hits. If you have a Seeker in your party, they can help out with No Stone Unturned, but that's a lot of cooperative building, and none of these solutions are XP-cheap (especially since Rabbit's Foot vies for the Accessory slot with the Amulet, so you won't be doing them in the first few scenarios.
The discard condition: You do the terrible thing, then this card becomes your discard pile.
All in all, this is a way above average signature weakness, and in competition for the worst weakness, able to wreck a scenario or end a campaign.
As cards come out that let you recurse from your discard, this card gets progressively worse. Resourceful, True Survivor now let you grab stuff in the discard and can become borderline (or totally) unplayable because of the risk posed by this card removing all the viable targets, Scavenging has always been a liability and these cards are only gonna grow in number. Thankfully Wendy is getting some solid cards like Waylay and Lucky Cigarette Case to slot next to Backstab and Rabbit's Foot and thus all 4 cards gain consistency.
Here'S hoping Wendy gets a novel though because I really would like to try True Survivor survivor on her.