- Treachery cards do not have a header for their subtitle. If the title of a treachery card contains 1 or more words in parentheses, that is considered to be its subtitle. Other cards with the same title and a different subtitle are still considered to be copies of one another. e.g. Restless Journey (Fallacy) and Restless Journey (Hardship) are both copies of Restless Journey. - FAQ, v.2.0, Card Ability Interpretation 2.21, see Treachery Subtitles.
Revelation - Secretly add this card to your hand.
You cannot play cards or commit cards to skill tests with an odd number of words in their title. (A word is any text separated by spaces.)
Discard a player card with an even number of words in its title from your hand: Discard this card from your hand.
LivefromBenefitSt's review of the first Law of this set pretty much sums up why this might be the most annoying Treacheries in the game.
Fun fact for this particular card is that, if I'm not mistaken, this is the first instance of an effect that fundamentally changes the game depending on the language you are playing (card titles differ in word length in different languages). So for example Look what I found! is playable while you hold Pandemonium and can be discarded to get rid of it if you are playing the game in English; while it's the opposite (dead card in hand) if you are playing in Spanish ("¡Mira lo que he encontrado!").
Having arkham player cards in Polish, English and Italian it is really fun dealing with these encounter cards. I purposely take 1 italian and 1 polish copy of, let's say, Magnifying Glass (Lente di Ingradimento) and have some fun :D