Luminous Broodmoth | Phyrexian Altar

(and one other card)

Creature with Persist or Undying

Activate
Phyrexian Altar by sacrificing the persist or undying creature, adding one mana of any color.
When the creature dies, its persist or undying ability triggers if it doesn't have a -1/-1 counter or +1/+1 counter on it respectively, and
Luminous Broodmoth triggers if the creature didn't have flying.
Resolve the persist or undying trigger, if applicable, returning the creature from your graveyard to the battlefield with either a -1/-1 counter or a +1/+1 counter on it.
Resolve the
Luminous Broodmoth trigger, if applicable, returning the creature from your graveyard to the battlefield with a flying counter on it if the creature is still in your graveyard.
Repeat.

You must choose a persist or undying creature that does not have flying - otherwise the
Luminous Broodmoth triggers do not occur.