Teshar triggers, returning Scrap Trawler from your graveyard to the battlefield.
Activate Delif's Cone by tapping and sacrificing it.
Activate Viscera Seer by sacrificing Scrap Trawler.
When Scrap Trawler dies, it triggers, returning Delif's Cone from your graveyard to your hand.
Resolve the Viscera Seer ability.
Repeat.
This looping marvel turns humble artifacts into an engine of endless recursion, fueled entirely by the graveyard-dredging power of Teshar, Ancestor's Apostle whenever you cast a historic spell. As you repeatedly play Delif's Cone, Teshar's trigger brings Scrap Trawler back to the battlefield, setting up an exquisite exchange of parts. Sacrificing Scrap Trawler to Viscera Seer triggers its own ability to fish the Cone right back out of the graveyard into your hand, while Viscera Seer simultaneously lets you sculpt the top of your library indefinitely.