Sefris of the Hidden Ways + Radiant Solar + Synth Infiltrator + Omni-Changeling

Sefris of the Hidden Ways

Radiant Solar

Synth Infiltrator

Omni-Changeling

How it works

1. Put any nontoken creature onto the battlefield.
2. When the creature enters, Radiant Solar, Omni-Changeling and Synth Infiltrator 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 Omni-Changeling trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Radiant Solar.
5. Resolve the Synth Infiltrator 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.