Photosynthesis

At the beginning of your upkeep the enchanted creature card adds {g} to your mana pool
You may pay {g}{g}{g} if you do, then next turn tap
the enchanted creature and put a +1/+1 counter
on it
"Take the gift of trees, harness the sun and wield it
as sword and shield"
—Eirfangh, Druid of Mowrghek Ien