Unda, Shaman of Life

{t}: Add another target creatures converted mana cost in any combination of colors to your mana pool. Unda, Shaman of Life doesn't untap during your next untap step.
Unda, Shaman of Life has hexproof as long as the total converted mana cost among creatures you control is 15 or greater.
Creatures you control with converted mana cost 7 or greater have trample.