Kandra, Deviant Telemin

When you cast Kandra, you may exile an instant
or sorcery card from your graveyard with
converted mana cost X or less, where X is the
amount of mana spent to cast Kandra, and put a
cache counter on it.
Whenever Kandra deals combat damage to a
player, choose a card in exile with a cache counter
on it at random. If you do, copy that card, then
cast the copy without paying its mana cost.