Argothian Elder, Griffin Canyon, and Rukarumel, Biologist

Prerequisites

• Argothian Elder on the battlefield
• Griffin Canyon on the battlefield
• Rukarumel, Biologist on the battlefield
• Argothian Elder does not have summoning sickness
• You control at least one additional land

Steps

1. Activate Argothian Elder by tapping it, untapping Griffin Canyon and another land
2. Activate Griffin Canyon's second ability by tapping it, untapping Argothian Elder and giving it +1/+1 until end of turn
3. Repeat

Results

• Infinite mana lands you control can produce
• Infinite untap of lands you control
• Infinitely large Argothian Elder until end of turn