William, the Wooden Warden

{t}: Add {g} to your mana pool.
Landfall — Whenever a land enters the
battlefield under your control, search your
library for an instant or sorcery spell and put it
into your hand. Then shuffle your library.
{1}{g}{t}: Discard a land you control. Target
creature gain indestructible until end of turn.
As long as there are five or less instant or sorcery spells in your graveyard, William isn't a creature.