Good Day,

Had this happen at a tournament last weekend, Grievous eliminated Dooku and the only upgrade available was the Holocron, the next round he rolled the special and swapped it out of for a a mind probe,
the question is what happens with the holocron? Does it go into the Grievous players hand? Or does it go into the discard pile of the original player?

Opponents cards never goes into your hand, this is a rule.

I think, but cannot confirm that holocron would be discarted.

Chak

because holocron has to swap with a card in hand to do the ability and because you cant have opponents cards in your hand you cannot use holocron special from a stolen holocron with grievous.

Sadly you got cheated there, hope it didn't impact the outcome of the game.

Edit:

Here is a quote from the Rules reference regarding cunning but the same principles apply:

Can I use Cunning (r65) to switch an opponent’s Sith Holocron (r16) with a card in my hand?

••No. You cannot have an opponent’s card in your hand or deck. The end result is that the Sith Holocron has no effect.