This has been updated to match my "Signature Weakness Project." I have done my best to make sure that the original content isn't altered too much, out of respect for any comments.
A very investigator-focused signature weakness. Looking at the two elements, the effect and the discard condition, we get:
The effect: At the start of a campaign, this card eats up about 4 actions, blocks Dr. Fern from useful horror healing, and messes up her economy for at least 2 turns. Which is pretty severe. The only way to mitigate it is get better horror healing, which comes with XP. A the start, horror healing acceleration is limited to Logical Reasoning, Soothing Melody, and Hypnotic Therapy. As XP accrues, 2 point healing gets reasonably common (which can be boosted to 3 with Hypnotic Therapy), and Logical Reasoning (4) can clear it in one action, if you have 2 clues. Ancient Stone:Minds in Harmony (4) can even do it as a reaction, assuming you can get 4 secrets on it and draw 4 cards. I personally like the idea of Kerosene, just because it seems like such an extreme therapy.... In most cases, a reasonably experienced Carolyn will clear it in 2 actions, which is not too bad.
The discard condition: Heal 4 horror off it, which, as noted above, gets easier as XP accrues.
When you think about it, this is an average signature weakness, maybe barely above average at low XP.
Box vs book It's better than To Fight the Black Wind in most situations, and it's paired with a much more useful signature asset, so most player will chose the "box" pair rather than the "book" set or doubling up, especially since having this and the Black Wind out at the same time are a horrible synergy.
