A modal double-faced card can be transformed or be put onto the battlefield transformed
A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation
This Jumbo Cactuar is one of them
That was the real strength of the card, you get to pay 2/3rds of the cost on a prior turn and only need to pay 1 mana on the turn you go off
The Bottom Line Japanese booster boxes deliver a fundamentally better opening experience than English boxes guaranteed rare pulls, superior print quality, and more consistent value in every box
What makes Bronze Guardian so good is that it extends that ward all the way out to your other artifacts as well