花（か）崗（こう）岩（がん）の凝（ぎょう）視（し）

Rulings oficiales · 2

wotc · 2013-04-15
If a permanent has {X} in its mana cost, the value of that X is 0.
wotc · 2013-04-15
The mana value of a creature token is 0 unless that token is a copy of another creature, in which case it copies that creature's mana cost.