When you cast G&G, the next 4 creatures in your library are destroyed.
When you cast PA, it returns himself from the graveyard when a Zombie comes into play.
So obviously this combination of cards should create a 8/8 defender each round (if destroyed previously). Even bigger defender if you have more PAs in a graveyard, but G&G puts exactly 4 there when they enter the battlefield.
But only one PA comes into play from the graveyard, creating a 4/4 defender only.
Or am I getting this game mechanic wrong?