Primordial Hydra enters the battlefield with X +1/+1 counters on it.

At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.

Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Serra Avatar's power and toughness are each equal to your life total.

When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Play with the top card of your library revealed.

As long as the top card of your library is black, Vampire Nocturnus and other Vampire creatures you control get +2/+1 and have flying.