Encroaching Mycosynth, Goblin Welder, Second Wind, and Tezzeret the Seeker

Prerequisites

• Encroaching Mycosynth on the battlefield
• Goblin Welder on the battlefield
• Second Wind on the battlefield
• Tezzeret the Seeker in your graveyard
• Goblin Welder does not have summoning sickness

Steps

1. Activate Goblin Welder by tapping it, sacrificing Second Wind and returning Tezzeret the Seeker from your graveyard to the battlefield
2. Activate Tezzeret the Seeker's first ability by putting a loyalty counter on them, untapping Goblin Welder and any other nonland permanent
3. Activate Goblin Welder by tapping it, sacrificing Tezzeret the Seeker and returning Second Wind from your graveyard to the battlefield attached to Goblin Welder
4. Activate Second Wind's last ability by tapping it, untapping Goblin Welder
5. Repeat

Results

• Infinite untap of nonland permanents