Persist Creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it and at least one +1/+1 counter on it due to
Bioengineered Future.
Remove a -1/-1 counter and a +1/+1 counter from the creature as a state-based action.
Resolve the
Bloodflow Connoisseur ability.
Repeat.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite death triggers.
Infinite creature sacrifice triggers.
Metadata
In 26 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).