Quest for the Slumbering Beast

Whenever a creature with power 4 or greater enters the battlefield under your control, put a quest counter on Quest for the Slumbering Beast.
Remove five quest counters from Quest for the Slumbering Beast and sacrifice it: Search your library for a creature card with power 4 or greater and put it onto the battlefield.
"We dreamed of meeting the world's strongest beast... And that dream came true." -Eirol, Sole Survivor