Rashmi, Plague Crafter

Whenever you cast your first spell each turn, reveal the top card of your library. If it's a nonland card with converted mana cost less than that spell's, you may cast that card without paying its mana cost. If you don't cast the revealed card, exile it and put a number of poison counters on target player equal to that card's converted mana cost.
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This card is dedicated to twighlight8. Thanks for the support!