Ocea, Soul of the sea

Convoke (Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
indestructible.
Annihilator 4.
When you cast Ocea, Soul of the sea you gain X life, where X is your starting life total.
When Ocea, Soul of the sea is put into a graveyard from anywhere, its owner shuffles his or her graveyard into his or her library.