Step 1: Sacrifice Nether Traitor to Phyrexian Altar for 1 mana of any color. Step 2: Generate Saproling token via Golgari Germination. Step 3: Sacrifice Saproling to Phyrexian Altar for 1 black mana. Step 4: Use floating black mana to re-cast Nether Traitor from the graveyard (tokens technically go to the graveyard when they die).
Repeat for infinite mana, ETB triggers, and dies triggers.