Gaeanus, the Shifting Forest

{1}{t}: Add {g}{1} to your mana pool.
Whenever Gaeanus, the Shifting Forest attacks, you may search you library for a card called Forest, reveal it, and put it into your hand. Shuffle your deck afterward.
"As an ecologist, I used to study the land here. It seems, though, like it's...alive."
-The Forestwalker's Journey