Intruder Alarm + Phantom Train + Xu-Ifit, Osteoharmonist

UB identity

Commander legal

The 3 combo pieces

• Intruder Alarm
• Phantom Train
• Xu-Ifit, Osteoharmonist

How to execute it

1. Activate Xu-Ifit by tapping it, returning a creature card from your graveyard to the battlefield.
2. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures.
3. Activate Phantom Train by sacrificing the creature returned in step 1.
4. Repeat.

What the combo produces

• Infinite +1/+1 counters on a creature
• Infinite creature LTB
• Infinite death triggers
• Infinite ETB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of creatures