Witching Hour:

Choose any number of Underworld character cards in your KO'd pile each with a cost of 2 or less. During your recruit step this turn, for each of those cards, you may recruit it as though it were in your hand, and you may pay 2 endurance rather than pay its recruit cost.

--

If the card is in my KO pile more than once, can I recruit it twice?

As an example: I Witching Hour and put Shelob in play for her effect. I then play a second Shelob in play, KOing the first Shelob. Can I recruit the KOed Shelob again, since she was targeted with Witching Hour?

As a point of terminology, Witching Hour doesn't target---you simply choose characters as part of its resolution.

To answer your question, though, no. When a card changes zones, it is no longer considered the same object. Shelob goes to the KO'd pile, but it cannot be considered the same Shelob you chose for Witching Hour.