Sefris of the Hidden Ways + Radiant Solar + Gigantoplasm + Stunt Double

Sefris of the Hidden Ways

Radiant Solar

Gigantoplasm

Stunt Double

How it works

1. Put any nontoken creature onto the battlefield.
2. When the creature enters, Radiant Solar, Stunt Double and Gigantoplasm 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 Stunt Double trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Radiant Solar.
5. Resolve the Gigantoplasm 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 intricate loop turns Sefris of the Hidden Ways into a relentless dungeon engine by exploiting a clever cycle of clones and legend-rule sacrifices. When you drop a creature into the mix, Radiant Solar triggers your venture while Stunt Double and Gigantoplasm enter as fresh copies of Radiant Solar to rapidly push you through the Tomb of Annihilation. The final room creates The Atropal token, and because you'll control multiple copies, the legend rule immediately sends the extras to your graveyard—which satisfies Sefris of the Hidden Ways's second ability to continuously resurrect Radiant Solar right back to the battlefield, letting you repeat the whole spectacle indefinitely.