Ono's Expertise

Until the end step of your next turn, whenever an opponent reveals or discards a card, that player loses life equal to its converted mana cost.
(If multiple cards are revealed, that player loses life equal to the combined converted mana cost.)
You may cast a card with converted mana cost 3
or less from your hand without paying its mana cost.
"Never strike until it's lethal" -- Ono's teachings