"without paying its cost" & cards with X cost

Salut,

Si j'ai une carte comme yog (de Scream Form Within) qui dit :
Action: Pay 2 to choose and play a Spell event card from your discard pile without paying its cost. Then, place that card on the bottom of your deck.

Et que j'utilise cette action pour récupérer Pushed Into The Beyond qui coûte X : 
Action: Choose a character card in play with cost X or lower. Then, shuffle that card into its owner's deck.

Comme on ne paye pas le X, à quoi équivaut le X dans ce cas là?

Merci!

X=0. Tu ne pourras cibler que des persos ayant un coût de 0.

faq, p.22 :

How does Yog-Sothoth Lord of Time
and Space’s (The Yuggoth Contract
F99) triggered ability which reads,
“Action: Pay 2 to choose and play a
Spell event card from your discard pile
without paying its cost. Then, place
that card on the bottom of your deck”
interact with X cost Spell event cards
in the owner’s discard pile ? Would
Yog-Sothoth be able to pay 2 to choose
a copy of Unspeakable Resurrection in
the discard pile to bring a character
of any cost into play from the discard
pile?

Yog-Sothoth interacts with X cost
spell event cards in the discard pile by
circumventing the cost of X being paid
entirely. However, because the cost of
X is not paid, X is defined as 0 for the
purposes of card effects that reference
it.

For example, if I use Yog-Sothoth’s
triggered ability and pay 2 in order to
play from my discard pile Unspeakable
Resurrection (which costs X), which
reads “Action: Choose a character in
your discard pile with cost X or lower.
Put that character into play.” I can only
put into play a character that costs 0
because I circumvented paying the cost
of the card.

Lire la FAQ c'est broken!