Ishora's colosseum

{t}: Add {1}.
{t}: Select a creature you control, then reveal
cards from the top of your library until you
reveal another creature, if that creature has a
lower combined power and toughness than the
selected creature's put it into play without paying
its mana cost, put the other revealed cards back
into your library, and then shuffle your library.
Otherwise sacrifice the selected creature, put the
revealed cards back into your library, and then
shuffle your library.