Katarina, Sinister Blade

Whenever Katarina attacks, you may pay
{2}{b}{r}, and discard an instant or sorcery. If you
do. Katarina deals damage equal to the discarded instant or sorcery's converted mana cost to the defending player and each creature that player controls. Remove Katarina from combat.
Whenever a player loses the game during your
turn, untap Katarina. After this phase, there is an additional combat phase.