Gravelgill Axeshark + Mikaeus, the Unhallowed + Phyrexian Altar

UB identity

Commander legal

The 3 combo pieces

How to execute it

  1. Activate Phyrexian Altar by sacrificing Gravelgill Axeshark.
  2. When Gravelgill Axeshark dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
  3. Activate Phyrexian Altar by sacrificing Gravelgill Axeshark.
  4. When Gravelgill Axeshark dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
  5. Repeat.

What the combo produces