The value of X is calculated only once, as Cloud of Darkness's last ability resolves
The cards weight is also a clue
Buried Alive costs the most to cast, but also fetches 3 specific cards for 3 mana, a rate that is unparalleled
Sure, theres a cute critter in the middle that many will likely care about exclusively, but its neat to see the TCG brew up a way for kids to immediately use their cards to play with each other and perhaps gain some interest in the full games rules
Players who use Grass or Metal deck can substitute Farfetch'd with Kartana, who has the same HP and attack power but with the added benefit of being able to hit weaknesses
The original "Polymerization" Normal Spell Card in particular is the most used "Fusion"/"Polymerization" Spell since it can be directly searched by a few "HERO" monsters: "Elemental HERO Blazeman", "Elemental HERO Spirit of Neos", "Elemental HERO Woodsman" and "Vision HERO Vyon"