The ninjutsu ability can be activated only after blockers have been declared
Invitations will go out via email, and the lucky few (thousand) will have a 72-hour window to purchase the cards
More importantly, from a purely cynical point of view, they're ripe for cross-promotion
Then exile it.) "Flashback [cost]" means "You may cast this card from your graveyard if the resulting spell is an instant or sorcery spell by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack." You must still follow any timing restrictions and permissions, including those based on the card's type
However, availability for certain items may fluctuate based on demand
Rarer than even enchanted, iconic cards use new art and a brand-new foil treatment that coats the card in glittering lore symbols and 3D hot stamp effects