You have at least eight permanent cards in your graveyard.
.
Mana Needed
({1} magic symbol) ({U} magic symbol) available.
Steps
Activate
Benthic Biomancer by paying ({1} magic symbol) ({U} magic symbol) , putting a +1/+1 counter on it.
Benthic Biomancer triggers, causing you to loot.
Starving Revenant triggers, causing you to gain 1 life and an opponent to lose 1 life.
Heliod triggers, putting a +1/+1 counter on
Benthic Biomancer.
Repeat from step 2.
Notes
If
Benthic Biomancer has a +1/+1 counter on it, you cannot use its adapt ability, and will need another way to put a counter on it. You can start the combo at steps 3/4 to accomplish this, or use any other method. This will also remove the mana requirement.