Melira, Sylvok Outcast + Ashnod's Altar + Putrid Goblin

Melira, Sylvok Outcast

Ashnod's Altar

Putrid Goblin

How it works

1. Activate Ashnod's Altar by sacrificing Putrid Goblin.
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to Melira.
3. Repeat.

This loop transforms a simple goblin into an infinite engine by exploiting how replacement effects interact with persist. When you sacrifice Putrid Goblin to Ashnod's Altar, its persist trigger normally would return it with a -1/-1 counter, but Melira, Sylvok Outcast's static ability completely prevents those counters from being placed on your creatures. Because the Goblin returns completely clean time and time again, you can sacrifice it indefinitely to fund Ashnod's Altar while generating an endless stream of enters-the-battlefield, leaves-the-battlefield, and death triggers.