Infinite +1/+1 counters on a creatureInfinite creature ETBInfinite creature LTBInfinite death triggersInfinite creature sacrifice triggers
How it works
Activate Bartolomé del Presidio by sacrificing the persist creature.
When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When the persist creature enters, Good-Fortune Unicorn triggers, putting a +1/+1 counter on the persist creature.
Resolve the Bartolomé del Presidio ability.
Repeat
This loop relies on Bartolomé del Presidio to continually feed your sacrifice outlets while using Good-Fortune Unicorn as an engine of continuous rebirth. Whenever your persist creature hits the graveyard, its native ability brings it right back, but weighed down with a -1/-1 counter. That is where Good-Fortune Unicorn comes in: its passive triggered ability immediately places a +1/+1 counter on the returning creature, which negates the -1/-1 counter through Magic's state-based action rules and leaves the creature completely ready to be sacrificed to Bartolomé del Presidio all over again.