We have ramp, lifegain, draw, discard, creature and planeswalkers removal that you can scale, and an ultimate that is fairly quickly reached
If you run Temur Sabertooth as a way to bounce Nikya to your hand, you could find yourself dropping an Eldrazi Titan on the back of a big Electrodominance or just bringing the table to its knees with an old fashioned Comet Storm
Just as important as the plant wurm creature is the spell Nature's Rhythm
But whatever card you think fits that description, these cards somehow cost even more (unless youre thinking of one on this list, of course)
Not only that, but this green creature also grows based on the number of creatures that were destroyed this way
However, it can't hit the same player twice in a turn