Krulax's Savagery

You may cast Krulax's Savagery any time you could cast an instant as long as you control an Abyssal creature. (Krakens, Leviathans, Octopuses and Serpents are Abyssal.)
Put a +1/+1 counter on target creature you control. Then that creature fights target creature you don't control.
Krulax's dominion is seldom challenged, and the bones of so-called challengers litter her territory.