Neddizem, the Hidden City

Neddizem, the Hidden City enters the battlefield tapped.
{t}: Add {u} or {g} to your mana pool.
{1}{u}{g}{t}: Target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back on top of your library or into your graveyard.)