Giant Decoy
(Mind 2/Arcane 1)
Targets zone or object
Mana cost: (2)(X)
Epic
When this enchantment is revealed, you gain mana equal to the total mana cost (both cast and reveal) The value of X is the number of times you have already gained mana by Giant Decoy's effect. After gaining mana this way, return Giant Decoy to your spellbook.
What do you think?