I'm working on a custom expansion and one of the locations is a curio shop. I thought a monkey's paw item might be kind of cool so I made an encounter for that, but I'm not sure if I have a strong enough penalty related to that, considering that you can gain any item you choose from any deck... What do you think? Here's the encounter as I currently have it:

Joe Carlson offers you the monkey paw behind the glass case for only $3. If you purchase it, you may make a wish for anything you want. Take any card from the Common, Unique, Exhibit or Spell decks. However, another Investigator (chosen at random) must take -1 Maximum Sanity and be knocked unconscious.

$3 is a little cheap for anything especially if you are including the exhibit deck. But costing another investigator maximum sanity is pretty harsh and kind of a jerk move on the part of the person facing the encounter.

If I recall correctly the paw granted a wish in such a way that it hurt the wish maker, so I'd have a skill check (probably Lore) to determine if you got what you want or the opposite to make $3 feesible. Heck, if you made some of the effects adverse enough you could make it a free item given to you by someone driven mad by it.

Some ideas: Common fail = Attacked by monster w/ physical/weapon immunity. Unique fail = Attacked by monster w/ magical/weapon immunity. Spell fail = Attacked by the Black Man. Attempt to seal a gate fail = sucked back in and delayed. etc etc

Well, what the monkey paw did in the story was grant a wish in a way that was also detrimental. The owners wished for $200 and they got $200 because their son was killed in a horrible factory accident. Then they wished he was alive again and you hear him scratching at the door, implying he's all mangled...

Of course, it would be hard (if possible at all) to replicate that kind of thing well within the AH system... the idea of a different penalty depending on what you choose is good... But I thought that a penalty hitting a fellow investigator (chosen at random), was sort of a way to simulate that. It doesn't affect you directly, but it hurts someone else (like the son getting killed) and also affects you (being part of the co-op team), and there's some uncertainty of who/how it will affect. And yeah, it seems like a jerky thing to do, but as a team you might decide it's worth it and tell the person, sure, go ahead and do it and grab an Elder Sign or a nice weapon.

Anyway, I'm still playing around with the idea. I really appreciate the input!

Also, if you're going to give someone -1 Maximum Sanity, you need to give them some sort of card or marker to indicate it. So the last bit ought to be something like "... if you do so, another investigator must take this card. Any investigator who has this card has -1 Maximum Sanity." It's a bit clumsy but it's not without precedent; a few OW encounters become semi-permanent things too.