A relatively simple but damaging signature . Looking at the two elements, the effect and the discard condition, we get:

The effect: The sharp needle in Joe's Insight haystack, this is going to cost you an action, 2 resources, and maybe a clue. Note that you can play it even if you don't have a clue, which makes it considerably less damaging. Joe needs to keep 2 resources on hand until this gets drawn, and it could cause an AoO if he is engaged when it comes up, but, despite the nasty effect if it fires, this is not a terrible threat. There is no particular mitigation, beyond making sure you have those resources or a quick way to get them. If Joe has somehow managed to translate the Cryptic Grimoire, he can play this fast. That Tome would generally help Joe, even if it's not hugely feasible for him to translate it without a cooperative Rogue or a lucky draw of the Dread Curse Weakness during deck building. Farsight could also help, but it's got a high opportunity cost for Joe. Other than that, there aren't a lot of card interactions. You can't even troll your party by playing Eidetic Memory, since Unsolved Case is removed from the game.

The discard condition: Another "one and done" Weakness, and one that removes itself from the game after playing, so it won't recur, even if Joe decks himself.

Summing up the facts, this is a way below average signature Weakness, in competition to be the easiest in the game.

A very good defensive card. With this in hand, even Winifred and Finn can pass Rotting Remains and Frozen in Fear and worse, for when "You handle this one!" isn't enough or in solo. It also pulls double duty as upgraded Daring Maneuver, allowing you to under-commit to tests you need to oversuceed by, particularly in Hard and Expert where it's impractical to cover the -6 -7 -8 otherwise.

Strong consideration for when the campaign feature nasty / treacheries that you need to pass. On my TCU solo Winifred run, this was one of the first upgrades to mitigate Bedeviled and Realm of Torment.

It's worth noting this is pretty good in the hands of Sefina Rousseau and Dexter Drake, particularly when running any of the hybrid Mystic events out of The Dream Eaters cycle: Spectral Razor, Ethereal Form, and Read the Signs.

These events test the base // of the associated Fight, Evade, and Investigate actions, adding your Will on top of them. With the Eye modifying that base, this lets Sefina and Drake test at 9 and 10, respectively, when using these events.

Both also have access to some methods for adding to the chaos bag (ex. Faustian Bargain) and a strong temptation to run Leo as an ally for bonus actions, making occasional the trigger appealing to them.

Just wanted to take a moment to appreciate how rarely this card screws you over. So often it spawns on a location that's already out of clues, or had none to begin with, or even already had a copy of fog on it, so does absolutely nothing. The only problem with that is that it stays out of the deck so it's not around to provide you with any more dead draws in the mythos phase, Its worst case scenarios are blocking a high shroud victory point location, and even then it's about worth a perception or flashlight charge. Adds +2 difficulty to something the seeker is already doing, and doesn't even block you from picking a clue.

I suppose it's a lot worse in higher difficulty levels, and it does block the strategy of flashlighting a location down to 0 shroud. But even in those scenarios, you have all the methods for picking up testless clues that you can just save for when this gets attached to a location.

Overall, I just can't think of any treachery that's shown up in a nail-biting mythos phase where certain cards will just force a loss, that gives as great a sigh of relief when it shows up instead of those. Though perhaps that's just because it's in so many levels.

Another flavorful signature Weakness. Looking at the two elements, the effect and the discard condition, we get:

The effect: Tommy likes Assets, and he likes putting damage and horror on them. This card requires the discipline to use those Assets carefully, so you only lose one or two. It's best if they are cheap (hello Cherished Keepsake and Leather Coat). You might not want to play Agency Backup until you've already drawn this, but Tommy's weakness and his strength is that his draw is terrible, and you may very well go several scenarios without seeing this particular problem. Tommy's access to 0-2 lets you pack Resourceful and Scrounge for Supplies to get the discarded cards back into your hand.

The discard condition: You draw it and either pay its cost or shuffle it back in. A rookie move, you might say.

Taken together, this is a below average signature weakness, unlikely to inconvenience Tommy too much in most scenarios and will almost never be the main reason you lose a scenario.