So, this card has an error on it. As written, the fight action does not cost ammo. However, Matt has already confirmed in the Mythos Busters discord server that this ability should function like every other firearm, so , spend 1 ammo: Fight.

I do not like Occult Lexicon; it's not a bad card in any way, just the first four words in the text complicate matters significantly: "limit one per deck":

Given how long scenarios typically last, and the punitive aspect of weaknesses that punish over-drawing, Arkham Horror LCG tends to leave a sizeable stack of cards left in your deck by the time a scenario ends, where even cards you've included two copies of have a chance of not showing up for any one scenario. This makes single copies in your deck very unreliable, and depending on them showing up early is ill-advised.

And Occult Lexicon value depreciates significantly the further into the game you draw it. After playing only one copy of Blood-Rite, you've broken even in terms of tempo: one action to play Occult Lexicon and one action to play one copy of Blood-Rite nets you two cards, two resources, two damage, or any combination thereof in two actions, what you would've gotten with basic actions. To get a return on investment, you need to draw one specific card, play it, play the other card that just entered your hand, wait till you draw one of the two remaining copies of that card, and then play a third card; a feat made unlikely to occur often with the deck limit.

You could always tutor Occult Lexicon out, there's Backpack and Research Librarian for that, but I advise against it, as it compounds the slow nature of Occult Lexicon. Now instead of spending two actions to get something back, you're spending three. Tutors are much better spent on impactful cards that you would be willing to spend two actions to have now rather than one later (or one and zero respectively it the card is fast). Occult Lexicon enriches your deck with better than average cards with high flexibilty; it's immediate impact is lacking.

Now despite all that, there's one sterling example of when Occult Lexicon might very well be an auto-include; in a Marie Lambeau deck. Marie wants spell assets or non-fast spell events to make use of her special ability, and Occult Lexicon enriches her deck with not just above-average cards, but above average spell events, eliminating their slow nature somewhat as they might as well be fast cards when played with her additional action. In addition, Hallowed Mirror works exactly the same as Occult Lexicon in this regard (and Marie can take both, as the're both lvl0 occult cards), with their respective spells being all-purpose enough that you're happy with drawing either. With that in mind, you can treat Occult Lexicon and Hallowed Mirror as a pair of a single card, just like any other card that you can include two copies of, which eliminates the other downside of those cards.

Some time has passed since this has been released. Altough there is an upgraded version, this still isn't the best card.

Altough there is an exception. It is Luke Robinson. As he can put it down on other locations, you can easily block a way of monsters, without stopping you at your place. If you use Open Gate as well you can build a wall, that only investigators can skip, but monsters are stuck behind.

EDIT: As can't add a different review I'm adding some new flavor to this one.

Ideas came and got official answer too.

TL;DR If you are 'as if' at a location and engage someone there (by taunting because normally you don't engage this way) when as if ends enemy stays with you as it is in your threat area. But even ending 'as if' shouldn't have transitions the enemy still moves when 'as if' ends, so barricade can stop it from moving with you.

Official answer: While investigating a connecting location using Pocket Telescope, for the duration of the investigation, you are investigating “as if you were there.” You are not physically there, so the enemies do not automatically engage you, but cards you play resolve with the “as if” condition in mind. Technically, you could then play Taunt to engage enemies at that location while investigating. Once the investigation ends, though, the barricade prevents any non-Elite enemies from moving into your location, so non-Elite enemies would not remain engaged with you.

EDIT: Grammar

I foresee Ethereal Form (and it's counterpart Read the Signs) becoming a staple among mystics, mostly due to innate attributes. All classes have an best stat, but there are also rather well-defined second-best stats and worst stats, as tabled below, calculated through averages of investigators' attributes within each class:

: Best Stat: , Second-Best Stat: , Worst Stat:

: Best Stat: , Second-Best Stat: , Worst Stat:

: Best Stat: , Second-Best Stat: , Worst Stat:

: Best Stat: , Second-Best Stat: and tied, Worst Stat:

: Best Stat: , Second-Best Stat: , Worst Stat:

Mystic's in particular is quite special due to every mystic except one having exactly 3 in that stat. Combined with no below 4 (expect Diana, but only technically), means that Ethereal Form will be testing at 7 minimum in all but Jim's hand (same for Read the Signs in all but Agnes's and Akachi's hand). It is also a spell, meaning the staple (and only, until Scroll of Prophecies came out) lvl0 mystic card draw Arcane Initiate will readily draw it.

Ethereal Form is of interest to Agnes Baker thanks to Heirloom of Hyperborea, of particularly interest to Marie Lambeau, thank to her innate ability, and of ESPECIALLY particular interest to Sefina Rousseau, thanks to her entire event-heavy play-style and whopping 8 test base for the card. Other non-mystics who can take mystic card and test Ethereal Form at 6 or above by default include Patrice Hathaway, Mandy Thompson, Lola Hayes, and, strangely enough, every Dunwich Legacy character.

That's all before we even get to what it does. It's closest comparison would be lvl0 Survival Instinct: same evade one, disengage all effect, and similar prevent re-engagement effect. It even has the same downside of possible screwing over fellow investigators at your location. The main difference is a 2 cost difference, a boost of 3 (on average) instead of 1 to the skill test, and the persistent, double-edged sword effect until round end. Your mileage may vary on the usefulness of a Survival Instinctesque card, but it's consistency is unquestionable; testing at 7 makes its effect a likely prospect, even on hard difficulty.

Oh boy. I just finished a campaign of TFA as Ursula Downs

First off, the good stuff. The flavor on this card is right on. Like many investigator weakness, it slows down or counteracts what your character is good at, and I feel like 2 horror is a reasonable penalty for failing to satisfy the call. This would be a pretty light penalty except....

The bad stuff. When you fail, you shuffle this card right back into your deck. On average, you'll draw this maybe once or twice a scenario and eat 0-4 horror. I had a few cases where I thought "tempo is more important than 2 horror, I'll just tank it" and draw the card again within a few turns. In other cases I drew or a -5 token and botched the investigate check. This led me to quickly nickname Dr. Elli Horowitz "Dr. Horror-soak". This is all well and good for a rough weakness, except....

The worst stuff. Spoilers for The City of Archives ahead. The fact that this scenario is part of the same campaign where Ursula debuted is a kick in the nuts! Not only are you stuck taking 2 actions to move and investigate, you still have to pass the investigation check with your measly 2 . They were at least fortunate enough to have Lost Humanity as part of the encounter set, unless like me you were unlucky enough to not remove Call of the Unknown from the game. Then you become left with a really small deck where you either keep paying 2 actions or keep taking 2 horror in quick succession. The only saving grace here is that Towers of Pnakotus exists to beef your deck back up, but even still, you want to be drawing lots of cards in this scenario. The Call will find you soon enough.

Ultimately, all I would want is some (reasonable) way to get rid of this card for good. Maybe something like "When you succeed on this investigation check for the first time in a round, place a resource on Call of the Unknown. Then if there are 3 or more resources on this card, discard it".