Roalesk, Apex Hybrid, Ashnod's Altar, Nim Deathmantle, and Gemstone Array

Prerequisites

• Roalesk, Apex Hybrid on the battlefield
• Ashnod's Altar on the battlefield
• Nim Deathmantle on the battlefield
• Gemstone Array on the battlefield
• A counter on Gemstone Array

Steps

1. Sacrifice Roalesk to Ashnod's Altar generating two colorless, with Roalesk's death you proliferate twice, putting two more counters on Gemstone Array
2. Remove those counters for two mana, use the other two mana from Ashnod's to return Roalesk to the battlefield using Nim Deathmantle
3. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite proliferate