Wild Evolutionary

Evolution {2}{g}{g} (Search your library for a green creature with converted mana cost of 3 or more and put it onto the battlefield, then shuffle your library. Move any enchantments and/or artifacts attached to Wild Evolutionary to that creature, then sacrifice Wild Evolutionary. Only activate this ability if Wild Evolutionary has 2 or more level counters on it)
Whenever a creature an opponent controls dies, put a level counter on Wild Evolutionary.