Dark Harbor Giant

{2}{u}{u}: Monstrosity 4. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Dark Harbor Giant becomes monstrous,
you may search your library for a creature card,
reveal it, and exile it. Then shuffle your library.
If you do, put X +1/+1 counters on this creature
equal to that creature's toughness.