Caldonia, the Lost Nation

Caldonia, the Lost Nation enters the battlefield
tapped.
{t}: Add {w}, {u}, or {b}. You lose 1 life.
{4}, {t}, Pay 2 life: Surveil 2. (Look at the top 2
cards of your library, then put any number of them
into your graveyard and the rest on top of your library
in any order.)