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 that creature as a state-based action.
Resolve the
Umbral Collar Zealot ability.
Repeat.
Results
Infinite creature ETB.
Infinite creature LTB.
Infinite death triggers.
Infinite creature sacrifice triggers.
Infinite surveil.
Metadata
In 199 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).