Mystery Box

Mystery Box enters the battlefield with 3 spin counters on it.
{5}, {t}, Remove a spin counter from Mystery
Box: Search your library for a card and exile it
face-down. Two opponents of your choice each
search your library for a card and exile it
face-down. Randomly select a card exiled this
way, reveal it, and put it in your hand. Shuffle
the other cards exiled this way into your library.
Then if Mystery Box has no spin counters on it, sacrifice it.