Ice-Rimed Mirror

Artifact
Whenever you play an instant or sorcery spell, if that spell's converted mana cost is equal to the number of cards in your hand, you may put a copy of that spell onto the stack. You may choose new targets for that copy.
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I wasn't sure if I wanted to make this a blue enchantment or an artifact. Once I came up with the name, I figured I should at least start with an aritafct in the spirit of Mirari. I think this is somewhat weaker than Mirari. Although it doesn't require a mana payment to create the copy, if places pretty strict limits on when you're allowed to make a copy, which I thought was a stronger drawback than a payment of

. Thus, I have costed this at

. If it needs to cost more, I would be willing to do that. I figured this would be an interesting way to play with the "hand-size matters" theme. Instead of rewarding having more cards than one's opponent or having seven or more cards, this card rewards careful management of hand-size and mana costs in hand. In some ways, I see its effect as similar to that of the Saviors Kirin creatures.