Death's Oasis | Deathrender | Elderfang Ritualist

(and one other card)

All permanents on the battlefield.
You have an Elf creature card in your graveyard with mana value four or greater.

Activate
Carrion Feeder by sacrificing
Elderfang Ritualist.
When
Elderfang Ritualist dies, it,
Deathrender and
Death's Oasis triggers.
Resolve the
Elderfang Ritualist trigger, returning an Elf creature card with mana value four or greater from your graveyard to your hand.
Resolve the
Deathrender trigger, putting the Elf with mana value four or greater from your hand onto the battlefield, and attaching
Deathrender to it.
Resolve the
Death's Oasis trigger, causing you to mill two cards and return a creature card with mana value two or less from your graveyard to your hand.
Activate
Carrion Feeder by sacrificing the creature with
Deathrender attached.
When the creature dies,
Deathrender and
Death's Oasis triggers.
Resolve the
Death's Oasis trigger, causing you to mill two cards and return
Elderfang Ritualist from your graveyard to your hand.
Resolve the
Deathrender trigger, putting
Elderfang Ritualist from your hand onto the battlefield, and attaching
Deathrender to it.
Resolve both
Carrion Feeder abilities from steps 1 and 6, putting two +1/+1 counters on it.
Repeat.