Kavana, Dark Rapture Mistress

Voidburn (Whenever this creature deals damage to an opponent player, that player loses 1 life each turn.)
Counter target spell. Its controller loses 3 life and
you gain 3 life.
At the beginning of your upkeep, choose target opponent. This turn, that player can't cast spells or activate abilities and plays with their hand revealed. You may play cards from that player's hand this turn.