Rex, Cyber-Hound, Pili-Pala, and Argothian Elder

Prerequisites

• Rex, Cyber-Hound on the battlefield
• Pili-Pala in exile
• Argothian Elder in exile
• You control at least two mana-producing lands
• Rex does not have summoning sickness
• Argothian Elder and Pili-Pala exiled with a brain counter on them

Steps

1. Activate Rex using Argothian Elder's ability by tapping it, untapping two lands
2. Activate two lands by tapping them, adding at least
3. Activate Rex using Pili-Pala's ability by paying and untapping it, adding one mana of any color
4. Repeat

Results

• Infinite colored mana
• Infinite untap of lands you control
• Infinite mana lands you control can produce