Death's Oasis | Deathrender | Workshop Assistant

(and one other card)

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

Activate
Carrion Feeder by sacrificing
Workshop Assistant.
When
Workshop Assistant dies, it,
Deathrender and
Death's Oasis triggers.
Resolve the
Workshop Assistant trigger, returning an artifact creature card with mana value four or greater from your graveyard to your hand.
Resolve the
Deathrender trigger, putting the artifact creature 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
Workshop Assistant from your graveyard to your hand.
Resolve the
Deathrender trigger, putting
Workshop Assistant 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.