Xavier Sal, Infested Captain, Intruder Alarm, Nazgûl, and Electroduplicate

Prerequisites

• Xavier Sal, Infested Captain on the battlefield
• Intruder Alarm on the battlefield
• Nazgûl on the battlefield
• Electroduplicate in hand
• Xavier Sal does not have summoning sickness
• available

Steps

1. Cast Electroduplicate by paying its mana cost, creating a token copy of Nazgûl
2. When the Nazgûl token enters the battlefield, its first ability and Intruder Alarm trigger
3. Resolve the Intruder Alarm trigger, untapping all creatures
4. Resolve the Nazgûl trigger, causing the Ring to tempt you
5. Each Nazgûl's second ability triggers, putting that many +1/+1 counters on each Wraith you control
6. Activate Xavier Sal's first ability by tapping it and removing a counter from a permanent you control, creating a copy of the Nazgûl token
7. Repeat from step 2

Results

• Infinite ETB
• Infinite creature tokens
• Infinite untap of all creatures
• Infinite mana creatures you control can produce
• Infinite copies of creature tokens you control
• Infinite +1/+1 counters on Wraiths you control