Kyler, Sigardian Emissary, Presence of Gond, Barrenton Medic, and Maskwood Nexus

Prerequisites

• Kyler, Sigardian Emissary on the battlefield
• Presence of Gond on the battlefield
• Barrenton Medic on the battlefield
• Maskwood Nexus on the battlefield
• Presence of Gond attached to Barrenton Medic
• Barrenton Medic does not have summoning sickness

Steps

1. Activate Barrenton Medic by tapping it, creating a 1/1 Elf Warrior creature token
2. The Elf Warrior enters the battlefield, triggering Kyler, putting a +1/+1 counter on itself
3. Activate Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it
4. Repeat

Results

• Infinite creature tokens
• Infinite ETB
• Infinitely large creatures