Human Fungusaur

Whenever you gain life, you may pay . If you do, put a +1/+1 counter on target creature for each 1 life you gained.

Flying Whenever a source an opponent controls deals damage to you, you may put that many +1/+1 counters on this creature.

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.