Glen Elendra Guardian + Mikaeus, the Unhallowed + Phantom Train

UB identity

Commander legal

The 3 combo pieces

• Glen Elendra Guardian
• Mikaeus, the Unhallowed
• Phantom Train

How to execute it

1. Activate Phantom Train by sacrificing Glen Elendra Guardian.
2. When Glen Elendra Guardian dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. Resolve the Phantom Train ability
4. Repeat.

What the combo produces

• Infinite +1/+1 counters on a creature
• Infinite creature LTB
• Infinite death triggers
• Infinite ETB
• Infinite sacrifice triggers