Teshar, Ancestor's Apostle + Scrap Trawler + Welding Jar + Yahenni, Undying Partisan

Teshar, Ancestor's Apostle

Scrap Trawler

Welding Jar

Yahenni, Undying Partisan

How it works

1. Cast Welding Jar by paying its mana cost.
2. Teshar triggers, returning Scrap Trawler from your graveyard to the battlefield.
3. Activate Welding Jar by sacrificing it.
4. Activate Yahenni by sacrificing Scrap Trawler.
5. When Scrap Trawler dies, it triggers, returning Welding Jar from your graveyard to your hand.
6. Resolve the Yahenni ability.
7. Repeat.

This elegant loop turns the lowly Welding Jar into a recursive engine by leveraging Teshar, Ancestor's Apostle and Scrap Trawler together. Whenever you recast the Jar, Teshar's historic trigger pulls Scrap Trawler back from the graveyard to the battlefield. From there, you sacrifice the Jar to its own regeneration ability and use Yahenni, Undying Partisan to sacrifice the Trawler, which in turn triggers the Trawler's retriever ability to bounce the Jar right back to your hand. Yahenni's sacrifice outlet acts as the safe engine room for the whole loop, letting you repeat this cycle endlessly while racking up an infinite storm count and endless artifact and creature triggers.