When The Earth King enters, create a 4/4 green Bear creature token.
Whenever one or more creatures you control with power 4 or greater attack, search your library for up to that many basic land cards, put them onto the battlefield tapped, then shuffle.
The Earth King's second ability counts the number of creatures with power 4 or greater you attack with when the ability triggers. Even if some or all of those creatures are no longer attacking or no longer have power 4 or greater when the ability resolves, they still count towards how many lands you can search for.