Sefris of the Hidden Ways + Radiant Solar + Sakashima the Impostor + Progenitor Mimic

Sefris of the Hidden Ways

Radiant Solar

Sakashima the Impostor

Progenitor Mimic

How it works

1. Put any nontoken creature onto the battlefield.
2. When the creature enters, Radiant Solar, Sakashima the Impostor and Progenitor Mimic each trigger.
3. Resolve the Radiant Solar trigger, causing you to venture into Tomb of Annihilation and into the Trapped Entry room, causing each player to lose 1 life.
4. Resolve the Sakashima the Impostor trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Radiant Solar.
5. Resolve the Progenitor Mimic trigger, venturing into the Cradle of the Death God room, creating a 4/4 legendary The Atropal creature token and completing Tomb of Annihilation.
6. If you control two or more The Atropal tokens, put all but one into your graveyard due to the legend rule.
7. Sefris' second ability triggers, returning Radiant Solar from your graveyard to the battlefield.
8. Repeat from step 2.

This clever loop turns dungeon-delving into a self-sustaining engine by orchestrating a continuous cycle of sacrifices and resurrections. With Sefris of the Hidden Ways providing the graveyard-to-battlefield recursion every time a creature bites the dust, your board state feeds directly into itself. When you introduce Radiant Solar, Sakashima the Impostor, and Progenitor Mimic—where the latter two enter as copies to multiply your entry triggers—each new creature entering the battlefield immediately propels you through the Tomb of Annihilation. The dungeon's final room sacrifices your Radiant Solar to the legend rule or discard mechanics, which conveniently drops it into the graveyard just in time for Sefris of the Hidden Ways to bring it right back, letting you repeat the entire cascade endlessly.