Urza, Brother of War

Whenever Urza enters the battlefield, you may
put a loyalty counter on any number of target planeswalkers you control.
Shroud, Flash
{2}{w}{u}{b}{r}{g}, {t}: Look at the top 7 cards of
your library. Choose and exile 3 cards from
among them, put the rest on the bottom
of your library in a random order.
You may cast planeswalkers and artifacts exiled
with Urza.