Kainu, Death Charmer

Allegiance (you may tap any number creatures you control while casting this spell. This creature enters the battlefield with a +1/+1 counter for each creature tapped this way.)
{1}:Turn your library upside down. Exile the top card of your library, you may cast that card until end of turn. Activate this ability only once per turn
Whenever a creature you control with less power than Kainu, Death Charmer dies, you may put it on the bottom of your library.