Infinite +1/+1 counters on creatures you controlInfinite charge counters on a permanentInfinite creature ETBInfinite creature LTBInfinite creature sacrifice triggersInfinite death triggers
How it works
Activate Spawning Pit by sacrificing Puppeteer Clique.
When Puppeteer Clique dies, its persist ability and Szarel trigger.
Resolve the persist trigger, returning Puppeteer Clique from your graveyard to the battlefield with a -1/-1 counter on it.
When Puppeteer Clique enters, it triggers, putting a creature card from an opponent's graveyard onto the battlefield under your control.
Resolve the Szarel trigger, putting a number of +1/+1 counters on another creature you control.
Resolve the Spawning Pit ability from step 1.
Activate Spawning Pit by sacrificing the creature returned in step 4.
When the creature dies, Szarel triggers, putting a number of +1/+1 counters on Puppeteer Clique.