Probably is a nooby question. Who pay and how much and when for to play this card and to destroy later?

http://deckbox.org/whi/Possess%20Mind

"Attach to a target unit. Action: At the beginning of your turn, attached unit deals damage equal to its power to target unit controlled by attached unit's controller. Then, any player may discard X cards from his hand to destroy this card."

Is it meant if the player who play the card pay for example 4 resource to attached this card to tartget unit than the opponent should discard 4 cards from his hand when he wants to destroy the attached Possess Mind?

Also I didn't get the rule text "... Then, any player may discard X cards from his hand to destroy this card." What is it stand for? Why would like anyone else to destroy the Posses Mind than the player of the attached unit's controller?

It needs to be worded that way because when you attach a card to an opponent's card, you still control your card. So yes, you pay for example 4 resources to attach Possess Mind to my unit, and at the beginning of your turn, the attached unit deals damage to a unit of mine of your choice. Then, either of us (or any other player, in a multiplayer game) may discard 4 cards to destroy Possess Mind. If it said "you may discard X cards ..." only you would be able to destroy it since you still control it, and unless the card mentions an exception, only the controller of a card may trigger its effects.

Thanks Mallumo. It makes sense. An other question. Can I target the attaced unit itself with the damage? It's not worded there target different unit so my understanding is yes it is possible. Do I understand right?

Correct. If the attached unit was excluded, it would have to say "... to another target unit ...", for example.

Just to make it more "intresting". Another question. Can I determine all the 4 discarded cards (stick to the above example) with help of the http://deckbox.org/whi/Dark%20Covenant?

Which says: " Attach to target unit. If a card would be discarded at random from the hand of attached unit's controller, you may instead look at that hand and choose and discard 1 card. "

Or in this case it's only true to the first randomly discarded card?

Possess Mind doesn't result in a random discard, it just says "discard", so Dark Covenant's effect doesn't apply. The player doing the discarding chooses the cards.

Damm it. You are right. I thought I can build up a multi combo action with this card. Ahyway thanks for the prompt replays. Cheers.

Also I didn't get the rule text "... Then, any player may discard X cards from his hand to destroy this card." What is it stand for? Why would like anyone else to destroy the Posses Mind than the player of the attached unit's controller?

I play Orcs. They get quite a benefit to have damaged units. I put Possess Mind on a 1-2 P unit of MINE. This way I can just power up my boyz turn by turn with damage triggered powers. And if I dont want, I just skip it, as it is not forced.

I guess YOU would discard a few of your cards to stop me doing this.

Also I didn't get the rule text "... Then, any player may discard X cards from his hand to destroy this card." What is it stand for? Why would like anyone else to destroy the Posses Mind than the player of the attached unit's controller?

I play Orcs. They get quite a benefit to have damaged units. I put Possess Mind on a 1-2 P unit of MINE. This way I can just power up my boyz turn by turn with damage triggered powers. And if I dont want, I just skip it, as it is not forced.

I guess YOU would discard a few of your cards to stop me doing this.