Splinter Twin, and Great Oak Guardian

Prerequisites

• Splinter Twin on the battlefield
• Great Oak Guardian on the battlefield

Steps

1. Activate Great Oak Guardian by tapping it, creating a token copy of itself with haste
2. When the token Great Oak Guardian enters the battlefield, it triggers, untapping all creatures you control and giving them +2/+2 until end of turn
3. Repeat

Results

• Infinite ETB
• Infinite creature tokens with haste
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinite power and toughness for creatures you control until end of turn