The Necrokitty

When you cast this spell, destroy all non-legendary creatures.
Whenever a creature would be put into a graveyard from anywhere, you may pay {1}, if you do, put that creature onto the battlefield under your control. That creature is a black zombie in addition to its other colors and types.
{5}{b}{b}: Destroy a target creature. Then, if you control 10 or more zombies transform The Necrokitty.