Spawning Pit | Resourceful Defense (and three other cards)

Persist Creature

Persist Creature

Increases +1/+1 Counter Placement but not -1/-1

Cards

Activate
Spawning Pit by sacrificing the Persist Creature that has a +1/+1 counter on it.
When that creature dies, its persist ability and
Resourceful Defense trigger.
Resolve
Resourceful Defense's ability, putting at least two +1/+1 counters onto the surviving Persist Creature due to the counter-increasing effect.
If that creature had a -1/-1 counter on it, remove that and one of the +1/+1 counters from it as a state-based action.
Resolve the persist ability from step 2, returning the Persist Creature from your graveyard to the battlefield with a -1/-1 counter.
Resolve the
Spawning Pit ability from step 1.
Repeat.

This combo has been estimated to be Exhibition (Bracket 1+).