Leonardo, Sewer Samurai + Solemnity + Sarcatog + Ornithopter

Leonardo, Sewer Samurai

Solemnity

Sarcatog

Ornithopter

How it works

1. Activate Sarcatog by sacrificing Ornithopter.
2. Cast Ornithopter from your graveyard by paying 0. It will not enter with a finality counter on it due to Solemnity.
3. Repeat.

This loop hinges on Leonardo, Sewer Samurai granting you the ability to cast Ornithopter directly from your graveyard during your turn, while Solemnity steps in to prevent the finality counters that would normally exile the tiny robot upon death. Once Ornithopter is back in your graveyard, Sarcatog can sacrifice it to fuel its own growth and clear the way for another casting. Because Solemnity blocks counters entirely, this artifact-recycling loop can repeat indefinitely, generating infinite death triggers and leaving Sarcatog infinitely large until end of turn.