Prophetic Owl

Flying
Cumulative upkeep {w/u} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever Prophetic Owl's cumulative upkeep cost is paid, look at the top X cards of your library, where X is the number of age counters on Prophetic Owl. You may put a card from among them into your hand. Put the rest on the bottom of your library in any order.