Overgrown Ruins

Overgrown Ruins enters the battlefield tapped.
{t}: Add {u}, {b} or {g}.
{u}{b}{g}: Overgrown Ruins becomes a 1/4 blue, black and green Elemental creature with deathtouch and "Whenever this creature deals combat damage to a player, look at the top two cards of your library. Put any number of them into your graveyard and the rest back on top of your library in any order.." until end of turn. It's still a land.