The first Enemy signature Weakness. Looking at the two elements, the effect and the discard condition, we get:

The effect: A relatively mild Enemy, the ghouls are likely to take Yorick 2 actions to dispatch, perhaps one if Vicious Blow or Brute Force are employed. If bad luck brings them out early, before Yorick has a chance to set up, they can be more troublesome, but no more so than a bad encounter deck draw. Their special ability is really only a problem if you are unlucky enough to draw them while engaged with one or more additional enemies

The discard condition: You kill them, which is something that Yorick is pretty good at doing. As usual, and investigator can deal with them, although Yorick rarely needs the help.

All in all, this is a below average signature weakness, generally offering only the mildest threat to the scenario.

Not a review, more of a question.

How does Improvised Weapon interact with this card while it is in your discard pile? Will it be forced to remain in your discard pile after completion of the attack, or it cannot even be played because you cannot fully resolve its effect??

I suspect you can still play it and it will be forced to remain in your discard pile after the attack resolves, but I'd like to see some opinions. If that would be the case, it would be a very interesting interaction.

This question, by the way, came up while trying to build a Yorrick deck using the upcoming Cornered card, in which Improvised Weapon would be a good addition as it would be great discard fodder for Cornered. I believe Cornered is going to be a great addition in William Yorick's arsenal and Improvised Weapon can find a slot or two in his deck. Looking forward to the release of the pack!!