Dirrara, Volcanic Dancer

Whenever Dirrara, Volcanic Dancer deals combat damage to a player, you may put a mountain card
from your hand onto the battlefield tapped.
{3}{r}{r}{r}{t}: Deal X damage to target creature
where X is the number of lands you control.
Deal X damage to the creature's controller where
X is the number of mountains you control
divided by 2 rounded up.