Prototype Portal, Ugin's Nexus, and Bartolomé del Presidio

Prerequisites

• Prototype Portal on the battlefield
• Ugin's Nexus in exile
• Bartolomé del Presidio on the battlefield
• each turn available

Steps

1. Activate Prototype Portal by paying and tapping it, creating a token copy of Ugin's Nexus
2. Activate Bartolomé del Presidio by sacrificing the Ugin's Nexus token
3. The Ugin's Nexus token is exiled instead of being put into your graveyard, causing you to take an extra turn after this one
4. Resolve the Bartolomé del Presidio ability, putting a +1/+1 counter on it
5. Repeat each turn

Results

• Infinite turns