Rathian, Terrestrial Tyrant

Partner with Rathalos, Aerial Emperor (When this creature enters the battlefield, target player may put Rathalos, Aerial Emperor into their hand from their library, then shuffle.)
Trample, Wither (It deals damage to creatures in the form of -1/-1 counters.)
{g}: Rathian, Terrestrial Tyrant fights target creature without flying an opponent controls. Activate this ability only as a sorcery.
Whenever a creature without flying enters the battlefield under an opponent's control, Rathian, Terre